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Biomedical subjects

S Y Song

Publications and source records attributed to S Y Song.

At least 91 records · Page 5Linked to original sources
PubMed1994

Use of bremsstrahlung radiation to monitor Y-90 tumor and whole body activities during experimental radioimmunotherapy in mice.

BACKGROUND: Large differences in uptake between tumors, even for the same size, frequently observed in clinical and experimental radioimmunotherapy (RAIT), make monitoring of uptake in individual tumors imperative in comparing protocols. 90Y, widely-used for RAIT, emits no gamma radiation and absorption of the beta particle in tissue makes its detection unsuitable for in vivo monitoring. We tested whether bremsstrahlung radiation, produced when betas are decelerated by nuclei, could be used to monitor tumor uptake. METHODS: Subcutaneous human LS174T colon carcinoma tumors were grown in the upper thigh of nude mice and labeled antibody injected intracardially. With the tumor placed in the 2 cm-diameter aperture in a lead collimator, photons with energies from 100 to 200 keV transmitted through plastic, which absorbed the beta particles, were counted to maximize shielding from the rest of the body. The contribution of the normal tissues was subtracted by counting the non-tumor-bearing leg in the same position. Excretion was calculated from whole body activity determined by removing the collimator, placing the mouse in a syringe surrounded by tissue-equivalent material 10 cm from the detector, and counting photons between 200 and 740 keV to minimize the effect of tissue attenuation. RESULTS: For tumors larger than 0.14 gm, a good correlation was obtained between the in vivo bremsstrahlung measurements and the measurements on excised tumors in a calibrated well counter. Similar excretion rates observed in all the animals suggested that the whole body counting was accurate. CONCLUSIONS: Bremstrahlung detection appears feasible and reliable for monitoring both tumor and whole body activities.

Animals↗
PubMed1994

Differential gene expression of fibroblast growth factor receptor isoforms in rat ovary.

The gene expression of four fibroblast growth factor receptors (flg, bek, FGFR-3, and FGFR-4) in rat ovary cells was studied. Northern blot hybridization revealed that flg and bek mRNAs were detectable during all stages except a diestrus stage, whereas FGFR-3 and FGFR-4 mRNAs were almost undetectable throughout the cycles. In situ hybridization also demonstrated that only flg and bek gene expression was detectable. A modest flg mRNA signal was detected in developing antral follicles and it was more prominent in the theca-interstitial cells than in the granulosa cells. A modest to weak flg mRNA signal was seen in the hypertrophied theca-interstitial cells of atretic follicles and a very weak flg mRNA signal was observed in the corpora lutea. On the other hand, a weak bek mRNA signal was seen in granulosa and theca-interstitial cells in developing follicles and also hypertrophied theca-interstitial cells of atretic follicles, but not in the corpora lutea. Intense signals for both flg and bek mRNAs were unexpectedly found in the epithelium of paroophoron at the hilus. These results demonstrate that the bFGF receptor isoforms are expressed differentially in the rat ovary cells.

Animals↗
PubMed1993

Structure of D-glyceraldehyde-3-phosphate dehydrogenase from Palinurus versicolor carrying the fluorescent NAD derivatives at 2.7 A resolution.

Ultraviolet irradiation of carboxymethylated D-glyceraldehyde-3-phosphate dehydrogenase leads to the formation of a fluorescent NAD derivative. The structure of the enzyme from Palinurus versicolor carrying this derivative has been determined by molecular replacement and refined using the restrained least-squares method to 2.7 A with a final crystallographic R-factor of 0.205. The polypeptide chain folding and subunit arrangement closely resemble the known structure of Homarus americanus GAPDH. The structure at the modified active site confirms that the photochemical reaction is a half-of-the-sites reaction and occurs in the red and yellow subunit pair. The stereochemical relationship between the Trp residues at the active site shows that Trp 310 is most probably involved in a radiationless energy transfer to the fluorophore. A large solvent channel connecting the catalytic and NAD(+)-binding sites was found parallel to the crystallographic axis alpha from packing analysis, suggesting that this crystal form may be suitable for a kinetic crystallographic study of the apoenzyme.

Animals↗
PubMed1992

An after-depolarization following action potentials and its modulation by substance P in rat sympathetic neurons.

Sympathetic neurons in rat coeliac-superior mesenteric ganglia (C-SMG) displayed an after-depolarization (ADP) following action potentials and after-hyperpolarization. The ADP had amplitudes of 3-10 mV and lasted for 2-6 s, during which membrane resistance and excitability of C-SMG neurons increased. The reversal potential of ADP was dependent on external K+ concentrations. The ADP was suppressed in a solution containing Cd2+ or zero Ca2+. The ADP thus appears to be produced by inhibition of certain K+ channels via a Ca(2+)-dependent process. Substances P (SP) depolarized ganglion cells and increased the ADP, leading to a long-lasting increase in membrane excitability of rat C-SMG neurons.

Action Potentials↗
PubMed1992

A rat cerebellar protein containing the cdc10/SWI6 motif.

Systematic analysis of soluble proteins in developing rat cerebellum by an automated two-dimensional liquid-chromatography system detected a number of proteins which increased transiently during the initial stage of postnatal development. One of the proteins, V-1, was isolated using a liquid-chromatography system, and its amino acid sequence was determined by analysis of the purified protein. The sequence showed that the V-1 protein consists of 117 amino acids with an acetylated N-terminus, and has 2.5 internal sequence repeats of 33 amino acids. Computer retrieval of the sequence indicated that the repeated sequences have a structural characteristics of the cdc10/SWI6 motif, which is found in a series of proteins, including those involved in cell-cycle control and cell-fate determination in yeast, Drosophila melanogaster and Caenorhabditis elegans. The structure of V-1, coupled with its controlled expression in early postnatal development, implies a potential role for V-1 in cerebellar morphogenesis.

Amino Acid Sequence↗
PubMed1992

Fast and slow depolarizations produced by substance P and other tachykinins in sympathetic neurons of rat prevertebral ganglia.

Using intracellular recording, we examined the effects of three mammalian tachykinins, substance P (SP), neurokinin A (NKA), and neurokinin B (NKB), on sympathetic neurons of isolated rat coeliac-superior mesenteric ganglia (C-SMG). The 3 tachykinins elicited two distinct depolarizing responses in ganglion cells: fast depolarization with time-to-peak of 1-2 sec and duration of 5-10 sec, and slow depolarization with time-to-peak of about 20 sec and duration of 120-140 sec. Both fast and slow responses persisted in a solution containing low Ca2+ and high Mg2+ or tetrodotoxin, which indicates that the tachykinins directly act on ganglion cells to produce fast and slow depolarizations. The two types of tachykinin-induced responses exhibited clearly distinguishable properties. The membrane conductance was increased during the fast response, but not significantly changed, slightly decreased or sometimes increased during the slow response. Within certain range of membrane potential, the amplitude of fast response increased upon membrane hyperpolarization and decreased upon depolarization of ganglion cells. In contrast, the amplitude of slow response associated with membrane conductance decrease was increased with membrane depolarization and decreased with hyperpolarization. The fast response was markedly suppressed in a Na(+)-deficient solution, a solution containing nominally zero Ca2+ (plus 0.1 mM EGTA in some cases), and in a solution containing Cd2+ or Mn2+, whereas the slow response was not affected in these solutions and was augmented in some cells in K(+)-free solution. Thus it seems that the increase in Ca(2+)-dependent cationic conductance underlies the fast response and that the slow response is produced at least in part by suppression of certain K+ channels. The fast response progressively decreased in amplitude upon repeated application of the peptides with short intervals, whereas the slow response was rather augmented by repeated application. Lowering the temperature markedly depressed the slow response, while the fast response remained almost unaffected. It is therefore likely that the fast and slow depolarizations are mediated by two different subtypes of tachykinin receptors or a single class of receptors linked with two different intracellular mechanisms. Measurement of tachykinins in several sympathetic ganglia by combined use of HPLC and radioimmunoassay revealed that the highest amount of SP occurs in the C-SMG where the content of SP (136.0 pmol/g protein) was higher than those of NKA (44.3) and NKB (18.7). SP thus appears to function as a major tachykinin in rat C-SMG.

Animals↗
PubMed1991

Adenine arabinoside monophosphate and acyclovir monophosphate coupled to lactosaminated albumin reduce woodchuck hepatitis virus viremia at doses lower than do the unconjugated drugs.

The woodchuck was selected to study the efficacy of liver-targeted antiviral drugs on hepadnavirus replication. Nineteen woodchucks chronically infected with woodchuck hepatitis virus were treated with adenine arabinoside monophosphate or acyclovir monophosphate, either free or conjugated with the liver-targeting molecule lactosaminated human serum albumin. Circulating woodchuck hepatitis virus DNA levels remained unchanged in untreated animals and in those receiving the carrier lactosaminated human serum albumin alone; in contrast, they were consistently lower after 5 days of treatment with the antiviral drugs. Free and conjugated adenine arabinoside monophosphate were active at doses of 10 and 0.75 mg/kg, respectively, and free and coupled ACVMP were active at doses of 20 and 2.6 mg/kg, respectively. These results indicate that the dosages of adenine arabinoside monophosphate and acyclovir monophosphate required to inhibit hepadnavirus growth can be sharply reduced by coupling the drugs to lactosaminated human serum albumin.

Acyclovir↗
PubMed1991

Adrenergic and cholinergic inhibition of Ca2+ channels mediated by different GTP-binding proteins in rat sympathetic neurones.

Effects of acetylcholine (ACh) and noradrenaline (NA) on voltage-gated ion channels of sympathetic neurones acutely dissociated from rat superior cervical ganglion (SCG) were examined using the whole-cell voltage-clamp technique. Depolarizing voltage steps elicited two types of low- and high-voltage-activated (LVA and HVA) Ca2+ currents. Pressure applications of ACh and NA produced concentration-dependent inhibition of the HVA Ca2+ current without affecting the LVA Ca2+ current. The inhibitory action of ACh on the Ca2+ current was blocked by a muscarinic antagonist, atropine. The action of NA was suppressed by an alpha 2-adrenergic antagonist, yohimbine, but not by an alpha 1-adrenergic antagonist, prazosin. Delayed rectifying outward K+ currents and inward rectifying K+ current were not affected by either ACh or NA. Tetrodotoxin-sensitive and -insensitive Na+ currents also remained unaffected under actions of ACh and NA. When recorded with electrode containing guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma-S), the inhibitory actions of ACh and NA on Ca2+ currents became irreversible. After treatment of SCG neurones with pertussis toxin, the inhibitory action of ACh on the Ca2+ current was almost completely abolished, whereas the action of NA was only partially reduced. The results suggest that ACh and NA differentially inhibit the HVA Ca2+ current via different G proteins coupling muscarinic and alpha 2-adrenergic receptors to Ca2+ channels in rat SCG neurones.

Acetylcholine↗
PubMed1991

[Receptor mechanisms underlying the actions of substance P and related neuropeptides].

The excitability of peripheral and central neurons is regulated by two types of ion channels, voltage- and ligand-operated ones. Recent studies have revealed that the activities of these ion channels are under the control of a variety of classical neurotransmitters and neuropeptides. In particular, certain ion channels such as voltage-dependent Ca and K channels are reciprocally regulated by excitatory and inhibitory neurotransmitters, leading to the excitation and inhibition of nerve cells: for example, 1) the activation of voltage-dependent K channel is facilitated by somatostatin and inhibited by substance P, and 2) the opening of voltage-gated Ca channel is augmented by substance P and suppressed by somatostatin and certain opioid peptides. The ligand-gated ion channel, nicotinic acetylcholine receptor is also controlled by the actions of neuropeptides, substance P and calcitonin gene related peptide (CGRP). The regulation of ion channels with neuropeptides may contribute not only to the control of neuronal excitability but also to the plasticity of the nervous system.

Animals↗
PubMed1989

Different GTP-binding proteins mediate regulation of calcium channels by acetylcholine and noradrenaline in rat sympathetic neurons.

In dissociated neurons of rat superior cervical ganglion (SCG), noradrenaline (NA) and acetylcholine (ACh) suppressed Ca2+ currents elicited by depolarizations to 0 mV from -60 mV. With GTP-gamma-S in patch electrodes, ACh and NA caused persistent inhibition of Ca2+ currents. Pretreatment of SCG cells with pertussis toxin abolished the action of ACh but not of NA. The results suggest that ACh and NA reduce the Ca2+ currents in SCG cells through different G proteins.

Acetylcholine↗
PubMed1989

Tachykinins produce fast and slow depolarizations in sympathetic neurons of rat coeliac-superior mesenteric ganglia.

The actions of mammalian tachykinins on neurons of rat coeliac-superior mesenteric ganglia (C-SMG) were examined using intracellular recording in isolated preparations. Application of substance P, neurokinin A and neurokinin B produced fast and slow depolarizations in the ganglion cells. The two responses were clearly distinguishable in their electrophysiological characteristics. The results suggest that different receptor mechanisms are involved in fast and slow depolarizing actions of tachykinins in rat C-SMG cells.

Animals↗
PubMed1989

[Cardiotoxicity of antipsychotic drugs: abnormal ECG in 1266 cases].

In this report, abnormal changes of 1266 ECG were assessed during antipsyhotic drugs medication. It was founded that cardiac dysrhythmia (sinus tachycardia) in the first place, T wave changes and depression of S-T segment in the next. The rate of abnormal ECG with chlorpromazine seemed to be higher than other drugs. Factors of dosage and time of treatment were non-significant.

Adult↗
PubMed1988

Inositol trisphosphate-linked calcium mobilization couples substance P receptors to conductance increase in a rat pancreatic acinar cell line.

The action of substance P (SP) on a rat pancreatic acinar cell line, AR4-2J, was examined using the whole-cell voltage-clamp technique. Pressure application of SP evoked inward currents accompanying increased membrane conductance. The SP-induced response was suppressed in Ca2+-free or low-Na+ solution. Treatment of cells with caffeine or A23187 produced a transient inward current and depressed the response to SP. Intracellular application of inositol 1,4,5-trisphosphate or guanosine 5'-O-(3-thiotriphosphate) elicited sustained inward currents and suppressed the SP-induced response. The results suggest that activation of SP receptors stimulates the formation of inositol phosphates via a guanine nucleotide-binding protein and leads to the rise in intracellular Ca2+, thereby activating a cation conductance in AR4-2J cells.

Animals↗
PubMed1986

[Value and factors of influence in the combined method of the urine-purple-heat tolerance test in the diagnosis of cancer].

A method combining the urine cancer reaction, purple reaction and heat tolerance test (combined method of urine-purple-heat tolerance) was used to examine 112 normal persons, 110 non-cancer patients and 93 cancer patients. It was found that the accuracy rate of the urine reaction was 82%, of the purple reaction 77.4%, and of the heat tolerance 79%. The combined method showed great diagnostic value for cancers in the digestive tract, such as stomach, biliary duct, colon, pancreas and liver, as well as other cancers, e.g., lung cancer, lymphosarcoma and brain tumor. This method may be best for screening the above tumors. Its positive rate was also high in malignant reticuloma, chronic granulocytic leukemia and reticulosarcoma. The mechanism of the combined method and the influential factors, such as the freshness of the specimen, reactive time, temperature and quality of the reagents are discussed.

Aldehydes↗
PubMed1986

Cerebral thrombosis at altitude: its pathogenesis and the problems of prevention and treatment.

In analyzing cerebral thrombosis at altitude--own case and in the literature--we anatomically confirmed that cerebral thrombi in mountain sickness were all of venous origin. All climbers went higher than 5,000 m and most stayed in that altitude longer than 3 weeks. Hemoconcentration was confirmed in two cases, including our own patient. It was suspected that hemoconcentration resulting from secondary polycythemia and dehydration at altitude, as well as cerebral circulatory disturbance produced by high-altitude cerebral edema, played a major role in the development of cerebral thrombosis. The problems of prevention and treatment of cerebral thrombosis at altitude are discussed.

Adult↗
PubMed1985

Neoplastic angioendotheliosis. Immunohistochemical and electron microscopic findings in three cases.

Three cases of neoplastic angioendotheliosis (NAE) presenting with central nervous system (CNS) disease but no skin lesions are described. The histogenesis of the neoplastic cells is discussed. Microscopic examination showed accumulation of neoplastic cells in the vascular system throughout the body and their extravascular proliferation in several organs. Electron microscopic and immunohistochemical studies revealed the presence of Weibel-Palade bodies and factor VIII-related antigen in intravascular and extravascular neoplastic cells in two of the three cases. In the first case the neoplastic cells did not have any T-cell markers. However, in one case no specific markers were found in the neoplastic cells by electron microscopic, enzyme histochemical, or immunohistochemical examination. These findings, although supporting the endothelial origin of the neoplastic cells, indicate the need for further consideration of whether NAE is actually a single disease entity or several different diseases.

Aged↗