Search PubMed⌕ Search

Biomedical subjects

S Y Hsu

Publications and source records attributed to S Y Hsu.

At least 73 records · Page 4Linked to original sources
PubMed1992

Fracture of the tibial spine in adults and children. A review of 31 cases.

We reviewed 19 adults and 12 children who had been treated for avulsion fractures of the tibial spine. Adult injuries have not previously been reported at length; most were caused by road-traffic accidents, and 68% were associated with other injuries, of which 58% were around the knee. The higher incidence of associated injuries in adults as compared with children, indicates that the injury is the result of greater energy and perhaps a different mechanism. The worse outcome in some adults was due to other associated intra-articular fractures and tears of the medial collateral ligament. Arthroscopy is useful in both diagnosis and treatment. Early accurate diagnosis and the correct treatment produce a good outcome.

Adolescent↗
PubMed1992

Generation of neutrophil-chemoattractant by degradation of tumor cell membrane protein.

Polymorphonuclear leukocytes (PMN) infiltrating into tumors are assumed to be the result of a migration in response to a tumor-derived chemotactic factor. It is hypothesized that tumor-derived chemotactic factors, which are supposed to be in aggregates, can be exposed by proteolytic degradation of the tumor cell membrane protein (TCM). The TCM suspension made from either Sarcoma 180 or Ehrlich ascites tumor after incubation with Varidase at 37 degrees C for six to eight weeks is referred to as a degraded TCM protein (DTCM). The purpose of this study was to detect whether or not the DTCM was chemotactic for PMNs. Chemotactic activity was assayed by a sponge-matrix model and expressed in the number of PMNs infiltrating into the sponge per mouse after intrasponge injection of the DTCM, dose range, 0.4-0.005 mL. Maximal response to DTCM was restricted to the limited dose between 0.01 and 0.02 mL. Quantities of DTCM > 0.02 mL caused a response in roughly reciprocal proportion to the dose of DTCM. Changes in the circulating leukocyte count in response to an intravenous (i.v.) injection of DTCM was biphasic. The initial relative leukopenia was followed by leukocytosis within 24 hours in rats surviving the effect of DTCM doses < 0.5 mL. However, in rats with i.v. injections of higher doses, profound leukopenia was present at death. The mice, after an intraperitoneal (i.p.) injection of DTCM, dose range, 0.5-1.0 mL, died between 16 and 24 hours after the injection. The bone marrow of these mice showed complete depletion of PMNs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Arthroscopic distension in the management of frozen shoulder.

We report a prospective study comparing the results of treatment for frozen shoulder by manipulation and physiotherapy, arthroscopic distension and physiotherapy, and physiotherapy alone in 75 patients. The first two gave better results than physiotherapy alone and we recommend arthroscopic distension as a good alternative to manipulation. It is more controllable and gives valuable information about the pathological lesions in the joint.

Adult↗
PubMed1991

Synergistic induction of ovulation and prostaglandin synthesis in goldfish (Carassius auratus) follicles by sodium orthovanadate and hydrogen peroxide.

The effects of hydrogen peroxide (H2O2) and sodium orthovanadate (Na3VO4) on ovulation and prostaglandin (PG) production were investigated in goldfish (Carassius auratus) follicles. H2O2, at levels that did not stimulate ovulation, significantly increased the ability of Na3VO4 to induce ovulation. The enhancing effect of H2O2 on Na3VO4-induced (10 microM) ovulation was observed over a wide range of concentrations (0.3-19.2 ppm) but was maximal at 1.2-4.8 ppm. The H2O2 effect on ovulation diminished at concentrations greater than 4.8 ppm. Na3VO4 and H2O2 also stimulated prostaglandin E (PGE) and prostaglandin F (PGF) levels in incubates. An interactive effect of the two agents was significant only on PGE production. However, optimal H2O2/Na3VO4 concentrations for the stimulation of PG production were much higher than those for stimulating ovulation. In most incubations, Na3VO4-induced or Na3VO4/H2O2-induced ovulation was not inhibited by the cyclooxygenase inhibitor indomethacin (IM), but was blocked by the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA). Treatment of an Na3VO4/H2O2 mixture with catalase before the start of incubation totally abolished the enhancing effect of H2O2 on ovulation. This suggests that the enhancing effect of H2O2 on ovulation may not be a result of a chemical metabolite(s) produced by the two agents in mixture but rather is due to some direct effect of H2O2. This may have physiological significance in light of the published effects of H2O2 on various processes known to be involved in ovulation.

Animals↗
PubMed1991

Secretory state of gastric mucosa does not protect against acute gastric mucosal injury induced by hemorrhagic shock in rats.

The protective effect of the secretory state of gastric mucosa against acute gastric mucosal injury due to hemorrhagic shock was investigated in rats with tetragastrin infusion. A total of 26 male Spraque-Dawley rats were divided into 3 groups (n = 6, 8, and 12, respectively). Tetragastrin (8 micrograms/Kg/h) was added into the normal saline infusion (5 ml/h) in group 3, but not in the other 2 groups. The mucosal surface was instilled with 0.1 N HCl (pH = 1) in group 2, with normal saline (pH = 7) in group 1, and with nothing in group 3. Hemorrhagic shock at 40 mmHg of arterial pressure was induced by withdrawing blood from the femoral artery, and was maintained at this level for 20 minutes; later, the shed blood was re-infused. During hemorrhagic shock, scattered areas of white circumscribed white lesions appeared on the mucosal folds of the glandular region in all of group 2 and in 8 (with gastric pH less than 3) of group 3, yet did not appear in group 1 or in the remaining 4 (with gastric pH greater than 3) of group 3. After reinfusion, varying degrees of mucosal hemorrhage from the whitened areas occurred in all of group 2 and in 8 (with pH less than 3) of group 3, but in only one of group 1. The severity of acute gastric mucosal injury in group 2 and group 3 (n = 8, with gastric pH less than 3) was significantly greater than group 1. However, it was not significantly different between groups 2 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Isolation of rat renal NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase.

Rat renal NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase was purified to apparent homogeneity in the present study. The purification included ammonium sulfate precipitation, DEAE-Sepharose CL-6B column chromatography, Blue Sepharose CL-6B column chromatography, Sephadex G-100 column chromatography and Mono-P isoelectrofocusing column chromatography. Among the chromatographies used, Mono-P chromatofocusing column of fast protein liquid chromatography gave the most powerful resolution. The enzyme was eluted at pH 6.75 on chromatofocusing column. It indicated that the rat renal enzyme is an acidic protein. Its molecular weight in SDS-polyacrylamide gel electrophoresis was 28 Kd, and the molecular weight of the enzyme having enzyme activity detected by gel filtration column chromatography was 55 Kd. For comparing the characteristics of rat renal enzyme with that of human placental enzyme, polyclonal antibodies and a monoclonal antibody against human placental enzyme were used. The rat renal enzyme did not react with the polyclonal antibodies of human placental enzyme, however, it reacted with a monoclonal antibody of human placental enzyme. The results indicated that the antigenicity of rat renal NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase is different from that of human placental enzyme. The amino acid composition of rat renal enzyme was also different from that of human placental enzyme. Nine tyrosine molecules were observed in the subunit of rat renal enzyme, while no tyrosine has been reported in human placental enzyme.

Amino Acids↗
PubMed1990

Antiplatelet action of dehydrokawain derivatives isolated from Alpinia speciosa rhizoma.

5,6-Dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK) inhibited the aggregation and ATP release of rabbit platelets induced by arachidonic acid and collagen, without affecting those induced by ADP, PAF and thrombin. This inhibition was reversible and in a concentration-dependent manner. The IC50 of DK and DDK on arachidonate-induced platelet aggregation were calculated to be about 10 and 60 micrograms/ml, respectively. Thromboxane B2 formation caused by arachidonic acid was also suppressed by both antiplatelet agents. DK inhibited the intracellular calcium concentration rised by arachidonic acid, but not that by collagen or thrombin. DK also inhibited the secondary, but not the primary aggregation of human platelet-rich plasma induced by ADP and epinephrine. It is concluded that the antiplatelet effect of both DK and DDK is due to the inhibition of thromboxane A2 formation.

Adenosine Triphosphate↗
PubMed1989

4-Aminopyridine induces the release of neuropeptide Y (NPY) to produce an atropine- and tetrodotoxin-resistant contraction in rabbit isolated jejunum.

4-Aminopyridine (4-AP) induced an atropine- and tetrodotoxin (TTX)-insensitive contraction (resistant contraction), in a concentration-dependent manner, in the isolated jejunum of rabbits. The failure of specific antagonists of histamine, serotonin and substance P to affect this resistant contraction ruled out the participation of histamine, serotonin and/or substance P. Antiserum against neuropeptide Y (NPY) reduced this resistant contraction in a concentration-dependent manner and inhibited the action of 4-AP totally at a high concentration (1.25% dilution) whereas normal serum lacked this ability. This suggested that the release of NPY was involved in this 4-AP-induced resistant contraction. Radioimmunoassay of NPY-like immunoreactivity in isolated synaptosomal preparations indicated that 4-AP possessed the ability to induce the release of NPY. However, guanethidine did not affect the actions of 4-AP, indicating that NPY is released mainly from non-adrenergic nerves. Our results indicate that 4-AP induces the release of NPY from non-adrenergic nerves to produce an atropine- and TTX-resistant contraction in the isolated jejunum of rabbits.

4-Aminopyridine↗
PubMed1989

Glutaraldehyde-treated bioprosthetic substitute for rabbit Achilles tendon.

The biomechanical properties and histocompatibility of a glutaraldehyde-treated xenograft were examined after implanting it in 27 rabbits. This xenograft was used as an Achilles tendon substitute placed in vivo for 2 to 48 wk. The specimens were then subjected to mechanical strength testing using a specially constructed tensioning device. The contralateral Achilles tendon was used as the reference baseline. Mechanical testing showed that the strength of the implanted graft increased to 33.5% of the normal side at week 10 and to 79.5% at week 14. The host generated a fibrous cord around the xenograft, linking the two ends of the Achilles tendon. Light and electron microscopic examination showed fibroblastic infiltration of varying magnitude in all specimens but no statistical correlation between degree of infiltration and duration of implantation was found. Also, there was no histological evidence of immunological rejection within the 48 wk of study.

Achilles Tendon↗
PubMed1989

Autoradiographic study of the attrition of migrating schistosomula in the skin of mice. I. Mice immunized with highly X-irradiated Schistosoma mansoni cercariae.

The migratory pattern in naive mice of Schistosoma mansoni cercariae X-irradiated with OkR, 12kR, or 48rR has been investigated with compressed organ autoradiography. Three groups of 69 mice each were infected with 75Se-labelled cercariae. The skin at the site of infection, as well as the entire lungs and liver were removed from infected mice daily from 1-21d, on 24d, and on 28d; tissues were then processed for autoradiography. Autoradiographic analysis of migratory patterns showed that the schistosomula derived from nonattenuated cercariae passed quickly from the skin to the lungs and at a moderate rate from the lungs to the liver. Schistosomula derived from 12kR-irradiated cercariae were delayed in passing from the skin to the lungs and from the lungs to the liver, so that many remained in the lungs and died there, while only a few died in the skin or liver. Schistosomula derived from 48kR-irradiated cercariae remained mainly in the skin, rarely reached the lungs and were never found in the liver. This study indicates that immunization with 48kR-irradiated cercariae will cause no significant lesions in the lungs or liver.

Animals↗
PubMed1987

Beta-subunit of Escherichia coli F1-ATPase. An amino acid replacement within a conserved sequence (G-X-X-X-X-G-K-T/S) of nucleotide-binding proteins.

A mutant strain KF87 of E. coli with a defective beta-subunit (Ala-151----Val) of F1-ATPase was isolated. The mutation is within the conserved sequence (G-X-X-X-X-G-K-T/S) of nucleotide-binding proteins. The mutant F1-ATPase had a much higher rate of uni-site hydrolysis of ATP than the wild type, and about 6% of the wild-type multi-site activity. The mutant enzyme showed defective transmission of conformational change(s) between the ligand- and aurovertin-binding sites.

Adenosine Triphosphate↗
PubMed1986

Use of bioprosthetic tendon in digital pulley reconstruction--an experimental study.

The potential clinical application of Glutaraldehyde treated bioprosthetic material in the hand as implants to substitute for damaged pulley, tendon or ligament has not been fully explored. This study tries to evaluate the efficacy and safety of the proposed bioprosthetic pulley in an experimental model. One of the digital flexor pulleys of the rabbit's foot was excised and replaced by a bioprosthetic pulley using a standardized technique. Autogenous tendon graft was used as the control on the opposite foot. Altogether twenty rabbits (40 feet) were included in the study and they were sacrificed at different time intervals up to one year. The retrievals were analysed for flexor tendon adhesions and rupture of the pulley macroscopically. Histological and Electron Microscopy study of the 'pulley' and 'pulley-bone' junction were also carried out. Results show consistently the progressive creeping substitution of the bioprosthetic material by the rabbit's own tissue without significant inflammatory reactions. Neither adhesions nor breakage of the pulley were detected, the results comparing favourably with the control group using autografts except for the longer time taken for the substitution process.

Animals↗
PubMed1984

Comparison of F1's of oxidative phosphorylation from Escherichia coli and Salmonella typhimurium and demonstration of interchangeability of their subunits.

The peripheral membrane portion (SF1) of proton-translocating ATPase of Salmonella typhimurium and its alpha, beta, and gamma subunits were purified and compared with the same portion (EF1) from Escherichia coli. The alpha, beta, and gamma subunits of these F1's were found to be mutually interchangeable, and all possible combinations of the three subunits from EF1 and SF1 showed ATPase activity. Both F1's could bind functionally to the integral membrane part (F0) of either bacterium, suggesting that F0 and F1 are interchangeable in these two bacteria and thus that the two F1's are closely similar at the level of subunit structure. However, SF1 differed from EF1 in some enzymological properties such as its specific activity and susceptibilities to sodium dodecyl sulfate and methanol. The specific ATPase activity of EF1 was more than twice that of SF1, and hybrid enzymes containing the beta subunit of EF1 had higher activity than other hybrids. Amino acid analysis suggested that the primary structures of the alpha subunits of the two F1's are less homologous than those of the beta subunits. Thus, the primary structure of the alpha subunit may be more species specific than that of the beta subunit.

Amino Acids↗
PubMed1978

Effects of theophylline and N6,O2-dibutyryl adenosine 3':5'-monophosphate on sympathetic ganglionic transmission in rats.

The effects of theophylline and N6,O2-dibutyryl adenosine 3':5'-monophosphate (DBcAMP) on the amplitude of the postganglionic action potential during and after a 10 Hz repetitive volley, and 50 to 1000 msec after a conditioning stimulus were investigated. The effects of both drugs on some electrophysiological properties of single cells of the isolated superior cervical ganglia of rats were also studied. At low concentrations of theophylline a reversible potentiation of the compound action potential occurred during and after repetitive stimulation at 10 Hz and also after the single conditioning stimulus. This effect was antagonized by atropine. Large concentrations of theophylline exerted a depressive effect only. Low concentrations of DBcAMP caused a reversible initial depression followed by a durable facilitation of transmission during repetitive stimulation. These concentrations potentiated the action potential amplitude after repetitive stimulation, but depressed it after a single conditioning stimulus. Atropine augmented the latter two effects. DBcAMP at large concentrations depressed transmission, but transmission was facilitated after drug washout. Theophylline and guanosine 3':5'-monophosphate, at ineffective concentrations when used singly, potentiated each other and elicited facilitation which was abolished by atropine. Theophylline and DBcAMP at these concentrations depolarized ganglion cells with a time course shorter than that of the aforementioned effects. Both drugs reduced the frequency and amplitude of the spontaneous miniature excitatory postsynaptic potentials. Theophylline did not increase the evoked transmitter release appreciably. On the basis of these findings and the evidence from literature, it is suggested that the reversible facilitatory effect of theophylline may be at least in part due to inhibition of phosphodiesterase of the ganglion cells leading to an enhanced muscarinic transmission. The prolonged facilitatory effect of DBcAMP may result from a durable change in the postsynaptic membrane structure leading to enhanced muscarinic transmission. An enhancement in the muscarinic transmission by both drugs increases the membrane excitability causing recruitment of subthreshold depolarized cells to discharge resulting in facilitation.

Acetylcholine↗