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Biomedical subjects

L Tsai

Publications and source records attributed to L Tsai.

At least 55 records · Page 3Linked to original sources
PubMed1993

Arthroscopic surgery of the knee in local anaesthesia. An analysis of age-related pathology.

Arthroscopy of the knee joint was performed in 356 consecutive outpatients in local anaesthesia and without premedication. A continuous pressure-irrigation system was used with 0.2% lidocaine chloride solution in the irrigation fluid, following administration of 5-7 ml prilocaine with epinephrine in each portal. All patients had clinical symptoms of internal derangement of the knee, such as meniscal, cruciate ligament injury or osteoarthritis. Associated intra-articular pathology was registered. Intra-articular surgery was performed in 228 cases. This included partial or subtotal meniscectomy in 207 cases and meniscus suture in 3 cases. In 18 of 228 cases (8%) the operative procedure had to be terminated due to patient discomfort. Of the meniscal injuries 84% were medial and 16% lateral. The age distribution of the medial meniscus tears was as follows: bucket handles 33 +/- 9 years; flap tears 42 +/- 10 years and degenerative tears 53 +/- 10 years. For the lateral meniscus the age distribution was: bucket handles 34 +/- 9 years, cleavage and radiating tears 37.5 +/- 12 years, flap tears 29 +/- 7 years, peripheral tears 32 +/- 9 years and degenerative tears 48 +/- 11 years. Osteoarthritis was observed in 52% of all medial degenerative tears, whereas a low frequency was found in the remaining tears. The majority of patients tolerated the procedure well. In summary, 64% of the consecutive arthroscopies were operative, including 3 meniscal sutures. Only 8% of these procedures had to be abandoned due to patient discomfort. Thus, arthroscopic surgery in local anaesthesia with no premedication is an efficient and well-tolerated method in outpatient practice.

Adult↗
PubMed1993

Isoforms of procarboxypeptidase B, (pancreas-specific protein, PASP) in human serum, pancreatic tissue and juice.

Human Pancreas-Specific Protein (PASP) has been described as a useful serum marker for pancreatic graft rejection and acute pancreatitis. By molecular cloning PASP has recently been identified as procarboxypeptidase B (PCPB). By use of SDS-gel electrophoresis and Western blots, PASP isoforms (proteins interacting with PASP-antiserum) have now been explored in serum and pancreatic tissue and juice. In serum from healthy volunteers, six different isoforms could be visualised. Their MW varied as follows: > 100 K, about 100 K, 45 K, 35-40 K (two bands) about 30 K and 16 K. The 45 K band, corresponding to PASP purified from pancreatic tissue, was always the major band. In pancreatic cytosol and pancreatic juice, the major band corresponded to PASP (45 K) but weak bands were also seen at MW of 40, 30 and 16 K. In serum from 15 patients with acute pancreatitis, PASP was highly increased. Bands corresponding to PASP/PCPB as well as carboxypeptidase B (CPB) were seen simultaneously. During recovery PASP in serum was normalised and the CPB band disappeared. During 12 episodes of pancreatic graft rejection, PASP in serum was also increased but no changes of isoforms in serum were detected. However during these episodes isoforms in pancreatic juice changed dramatically. The band corresponding to PASP disappeared or became much weaker and only bands with lower MW were seen. We have thus observed changes in PASP/PCB serum isoforms during episodes of acute pancreatitis but not at graft rejection episodes although the total increase of PASP in serum was of the same magnitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Effect of okadaic acid on hepatocyte structure and function.

The aim of this study with rat hepatocytes was to describe the effect of okadaic acid (OKA) (a potent and specific inhibitor of protein phosphatases) on the biosynthesis, processing and/or secretion of various lipid and protein molecules. Gel radioautograms indicated that low concentrations of okadaic acid (100 nM) induced hyperphosphorylation of a number of hepatocyte phosphoserine/threonine residues in the Mr range of 35-220 kDa. The effects of okadaic acid on the morphology of the hepatocytes was time and dose-dependent; early changes included cell rounding, loss of typical Golgi staining of beta COP, and fragmentation of the Golgi compartment at the EM level. General hepatocyte cell functions such as protein synthesis, lactate dehydrogenase activity, and ATP levels were unchanged with 100 nM okadaic acid as were all hepatocyte functions carried out in the endoplasmic reticulum of these cells. As such, incubation with okadaic acid did not alter the biosynthesis of phosphatidylcholine (from labeled choline), or very low density lipoproteins (VLDL) from labeled fatty acids or glycerol. Likewise, the biosynthesis of various endoplasmic reticulum synthesized proteins (transferrin, albumin, apolipoprotein E, and HMG CoA Reductase) continued normally in the presence of okadaic acid. However, incubation with okadaic acid led to major changes in all hepatocyte functions normally carried out in the Golgi compartment; i.e., the incorporation of labeled ceramide into sphingomyelin was profoundly reduced, as was the Golgi-required packaging and secretion of various proteins synthesized in the endoplasmic reticulum. These findings point to the Golgi compartment as an specific target for okadaic acid and suggest that one or more okadaic acid-sensitive phosphoproteins may be involved in maintaining its normal structure and function.

Animals↗
PubMed1992

Synthesis of 5-methylaminomethyl-2-selenouridine in tRNAs: 31P NMR studies show the labile selenium donor synthesized by the selD gene product contains selenium bonded to phosphorus.

An enzyme preparation from Salmonella typhimurium catalyzes the conversion of 5-methylaminomethyl-2-thiouridine in tRNAs to 5-methylaminomethyl-2-selenouridine when supplemented with selenide and ATP. Similar preparations from a Salmonella mutant strain carrying a defective selD gene fail to catalyze this selenium substitution reaction. However, supplementation of the deficient enzyme preparation with the purified selD gene product (SELD protein) restored synthesis of seleno-tRNAs. In the absence of the complementary enzyme(s), the SELD protein catalyzes the synthesis of a labile selenium donor compound from selenide and ATP. 31P NMR studies show that among the products of this reaction are AMP and a compound containing selenium bonded to phosphorus. The reaction is completely dependent on the addition of both selenide and magnesium. The dependence of reaction velocity on ATP concentration shows sigmoidal kinetics, whereas dependence on selenide concentration obeys Michaelis-Menten kinetics indicating a Km value of 46 microM for selenide.

Adenosine Monophosphate↗
PubMed1992

ADHD and PDD.

Explore the source record for details and available documents.

Attention Deficit Disorder with Hyperactivity↗
PubMed1992

Effect of cortisol on the secretion of testosterone and estradiol-17 beta by human granulosa-luteal cell cultures. A model system for analyzing hormonal alterations in female athletes.

The combination of hypercortisolism and usually low androgen and estrogen levels is frequently observed in female long distance athletes. In order to find a useful model system for studying the underlying mechanisms, the following studies were performed. The effect of cortisol on the secretion of testosterone (T) and estradiol-17 beta (E2) by human granulosa-luteal cells was studied in vitro in cultures of cells recovered from mature follicles of gonadotrophin stimulated women (participating in the IVF program). Following 24 hours of culture in tissue culture medium without hormonal additives, the granulosa-luteal cells were incubated for 6 hours in media with addition of 4-androstene-3,17-dione (A-4) as precursor and hMG and cortisol in different combinations. The secretion of T was significantly stimulated by cortisol but not by human menopausal gonadotrophin (hMG). Cortisol, but not hMG, also increased the secretion of E2, although this effect was not statistically significant. These in vitro findings make a direct effect of cortisol upon ovarian sex steroid secretion less likely as the mechanism behind the subnormal sex steroid levels in female long distance athletes. Instead, inadequate gonadotrophic stimulation, related to hypothalamic amenorrhea, and/or a selective decrease in the adrenal secretion of precursor steroids, may be an explanation.

Estradiol↗
PubMed1992

Mood disorder in a group of self-cutting adolescents.

This study describes the occurrence of mood disorder in a group of adolescent inpatients involved in self-cutting behavior. Although self-cutting is generally said to be associated with borderline personality disorder, a substantial number of patients who cut themselves in our study were clinically depressed. In addition, the self-cutting adolescents had a high prevalence of child abuse, past psychiatric history, and family psychiatric history. The incidents tended to spread by contagion and occur at times of change affecting the milieu. Clinical implications of these findings are discussed.

Adolescent↗
PubMed1991

Okadaic acid interferes with lipoprotein-supported corticosterone production in adrenal cells.

Rat adrenocortical cells in culture respond to stimulation by ACTH alone (15 fold over basal) and to ACTH + added lipoproteins (as an exogeneous source of cholesterol), with an additional 25-30 fold rise in steroidogenesis. With the addition of okadaic acid (OKA, 100 nM), a potent protein phosphatase inhibitor, the lipoprotein-induced rise in steroidogenesis is blocked. If 20 alpha-hydroxycholesterol is provided instead of lipoprotein-cholesterol, OKA has no effect suggesting that OKA affects only actively transported cholesterol. Since the OKA block is preceded by specific morphological changes in the cell (i.e., the loss of Golgi-associated microtubules followed by the disruption of the Golgi apparatus itself), it is hypothesized that some OKA-sensitive phosphoprotein associated with the microtubule/Golgi network of adrenocortical cells is critical for lipoprotein-derived cholesterol uptake and/or transport during steroidogenesis.

Adrenal Cortex↗
PubMed1991

Cortisol and androgen concentrations in female and male elite endurance athletes in relation to physical activity.

To evaluate the effect of variations in physical activity on selected hormone concentrations in male versus female athletes, fasting serum concentrations of cortisol (C), total-testosterone, free-testosterone, non sex hormone binding globulin (SHBG) bound testosterone, dehydroepiandrosterone, 4-androstene-3,17-dione and SHBG were studied. The tests were performed in nine male and seven female elite endurance athletes during the off-season (test 1), early in the competition season (test 2) and at the end of the competition season (test 3). The C concentration increased significantly during the competition season in women but not in men. Further, the mean C concentrations at test 3 as well as the mean level during the whole observation period (tests 1, 2, 3) were significantly higher in women than in men. No significant changes were found in androgen concentrations or androgen:cortisol ratios within the two groups. The differences between the sexes in C response may indicate different adaptive mechanisms to similar physical stress.

Adult↗
PubMed1991

Depression in autistic disorder.

Depressive illness in a patient with Down's syndrome and autism responded to fluoxetine. The importance of diagnosing superimposed depression in people with developmental disorders is emphasised.

Adolescent↗
PubMed1990

Uptake and utilization of lipoprotein cholesteryl esters by rat granulosa cells.

Earlier studies have shown that rat granulosa cells grown in serum-free medium are exquisitely responsive to exogenously provided lipoprotein cholesterol. In this study we compare the amount of cholesterol (cholesteryl ester) actually delivered from various homologous and heterologous cholesterol-rich lipoproteins and examine the intracellular pathways used in the delivery system. Granulosa cells were incubated for 5 or 24 h with 125I-labeled human (h) HDL3, rat (r) HDL or hLDL equipped with non-releasable apoprotein and cholesteryl ether tags which accumulate within cells, even after degradation. We show that all the tested lipoproteins were similarly efficient in cholesteryl ester delivery; i.e., based on cholesterol: protein ratios of the starting ligands, each delivered approximately the same cholesteryl ester mass and evoked a similar progestin response. However, each lipoprotein was processed quite differently by the granulosa cells: hHDL3-cholesteryl ester was taken up almost exclusively by an non-endocytic pathway, hLDL-cholesteryl ester almost exclusively by an endocytic pathway and rHDL-cholesteryl ester by both pathways. In general, there was no correlation between the total amount of lipoprotein bound or apoprotein internalized and/or degraded by the cells with the amount of cholesteryl ester received or the level of the progestin response. Hormone stimulation upregulated the preferred pathway for each lipoprotein.

Animals↗
PubMed1990

Restoration of anabolic deficit and muscle glycogen consumption in competitive orienteering.

Consumption and restoration of muscle glycogen and changes in anabolic and catabolic steroid hormones were analyzed in five male elite orienteers during and after an orienteering competition. The magnitude of glycogen consumption and pronounced increase in serum-cortisol during the orienteering race reflect the great muscular output demands during forest running. The free testosterone/cortisol ratio was normalized to the initial level within four hours post-exercise. Synchronously, only 25% of the muscle glycogen loss was restored. Within 24 hours post-exercise all runners showed normalized levels of testosterone, cortisol and free testosterone/cortisol ratio. The glycogen content was also restored except in one of the runners. We conclude that daily orienteering competitions per se do not seem to create risks for developing a state of hormonal imbalance or significant decrease in glycogen when the carbohydrate supply is appropriate.

Adult↗
PubMed1990

In vitro incorporation of selenium into tRNAs of Salmonella typhimurium.

Broken-cell preparations of Salmonella typhimurium rapidly incorporated 75Se from 75SeO3(2-) into tRNA by an ATP-dependent process. Selenium incorporation in the presence of 50 microM 75SeO3(2-) (0.8-1 pmol per A260 unit) was enhanced by the selenocysteine precursor, O-acetyl-L-serine (to 3.7 pmol per A260 unit). This increase in incorporation was a function of O-acetyl-L-serine concentration. Neither O-acetyl-L-homoserine nor O-phospho-L-serine stimulated the incorporation of selenium into tRNA. The incorporation of 75Se from 75SeO3(2-) was decreased by adding L-selenocysteine but not by adding the D isomer. When homologous bulk tRNA was added to the broken-cell preparations, an increased rate of 75Se labeling was observed. The supernatant fraction of the broken-cell preparation contained all of the enzymes required for this process. Reversed-phase HPLC analysis of labeled bulk tRNA digested to nucleosides showed the presence of a labeled compound that coeluted with authentic 5-methylaminomethyl-2-selenouridine.

Adenosine Triphosphate↗