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Biomedical subjects

Y S Hwang

Publications and source records attributed to Y S Hwang.

At least 19 recordsLinked to original sources
PubMed1992

Sparganosis in the spinal canal with partial block: an uncommon infection.

A case of rare intraspinal sparganosis treated by surgical excision is described. In this 59-year-old male with paraparesis and voiding problem, an intradural mass was noted on myelogram. Magnetic resonance (MR) and computed tomographic appearance of spinal and associated cerebral lesion are illustrated and possible route of migration discussed. This represents, to our knowledge, the first MRI demonstration of intraspinal sparganosis reported in the literature.

Humans↗
PubMed1992

Effects of thromboxane synthase and cyclooxygenase inhibition on PAF-induced changes in lung function and arachidonic acid metabolism.

PAF was administered as an intravenous bolus (0.1 micrograms/kg) to eight chronically instrumented awake sheep. The effects of pretreatment with an inhibitor of cyclooxygenase (meclofenamate) on PAF-induced changes in lung function were compared to those observed with a specific inhibitor of thromboxane synthase (DP1904). Each animal was studied four times in varied order: PAF alone, PAF + DP1904, PAF + meclofenamate, and DP1904 alone. Saline alone (control), DP1904 alone, and meclofenamate alone did not cause changes in any of the measured variables. DP1904 and meclofenamate significantly attenuated the PAF-induced fall in lung compliance, elevation in peak pulmonary artery pressure, and increased lung lymph flow. Both drugs abolished the PAF-induced increases in lung lymph thromboxane B2 concentrations. Meclofenamate, but not DP1904, blocked the rise in lymph 6-keto-PGF1 alpha. Although meclofenamate blocked the rise in lymph PGE2, DP1904 resulted in levels 2.7 times higher than PAF alone. We conclude that: (1) inhibition of thromboxane synthase is as effective as inhibition of cyclooxygenase in attenuating PAF-induced changes in lung function, and (2) thromboxane synthase inhibition results in augmented production of PGE2 following PAF administration in vivo.

Animals↗
PubMed1991

Is sick sinus syndrome an adenosine-mediated disease? Effects of intravenous aminophylline on sick sinus node function after pharmacologic autonomic blockade.

To assess the effects of intravenous aminophylline on the sinus node, 12 patients with clinical and Holter monitor-documented sick sinus syndrome were studied (1) during the control state, (2) after pharmacologic autonomic blockade and (3) 5 min after intravenous administration of aminophylline. The effects of aminophylline on sinus node function were compared with those after pharmacologic autonomic blockade. No significant improvement of sinus node function was found after intravenous aminophylline administration with a mean sinus cycle length and a mean maximum CSRT of 968 +/- 218 and 1832 +/- 1036 ms, respectively. The mean serum theophylline level was 10.9 +/- 1.7 micrograms/ml. Since aminophylline is an adenosine receptor antagonist, these findings suggest that intrinsic adenosine may not play an important role in pathogenesis in patients with chronic and advanced sick sinus syndrome.

Adenosine↗
PubMed1990

Phase II Radiation Therapy Oncology Group study of hormonal cytoreduction with flutamide and Zoladex in locally advanced carcinoma of the prostate treated with definitive radiotherapy.

In patients with locally advanced (bulky) carcinoma of the prostate, definitive radiotherapy is associated with a high rate of local recurrence. The Radiation Therapy Oncology Group (RTOG) has conducted several studies evaluating hormonal cytoreduction (used as an induction regimen) as a means of improving the local control rate. RTOG 85-19 tested an induction regimen consisting of a depot LH-RH agonist (Zoladex) and an antiandrogen (flutamide). Eligible patients were those with bulky primary lesions (stage B2 and C) with disease confined to the pelvis. Zoladex was administered every 29 days via a subcutaneous injection. Flutamide was given by mouth in a dose of 250 mg t.i.d. Administration of the drugs was initiated 2 months prior to start of radiotherapy and was terminated at completion of the radiotherapy course. Radiotherapy consisted of 180-200 rad/day, 4,400-4,500 rad to the regional lymphatics, and 6,500-7,000 rad to the prostate. The primary aim of the study was to evaluate the effectiveness and toxicity of the combined (hormonal cytoreduction plus definitive radiotherapy) regimen. Thirty-one patients were accessioned; 30 are analyzable. The drug-related toxicity appears acceptable. It included appearance of diarrhea before initiation of radiotherapy in two patients, nausea during the 2nd week of drug administration in two patients, and skin rash in three patients. These phenomena appear to be related to flutamide. Hot flashes were recorded in 17 patients. With a minimum follow-up of 2 years, clearance of the primary lesions (by clinical examination) was documented in 28 of 30 patients. During the 1st year, two of 30 patients died (of unrelated causes) with residual palpable tumors. The observed toxicity appears acceptable and the response rate encouraging. A phase III study comparing the tested regimen against radiotherapy alone appears warranted.

Buserelin↗
PubMed1989

Structure and expression of the rice glutelin multigene family.

A near full-length cDNA and three genomic clones for rice (Oryza sativa L.) glutelin were isolated and studied. Based on nucleic acid sequence and Southern blot analyses, the three isolated glutelin genomic clones were representative members of three gene subfamilies each containing five to eight copies. A comparison of DNA sequences displayed by relevant regions of these genomic clones showed that two subfamilies, represented by clones Gt1 and Gt2, were closely related and evolved by more recent gene duplication events. The 5'-flanking and coding sequences of Gt1 and Gt2 displayed at least 87% homology. In contrast, Gt3 showed little or no homology in the 5'-flanking sequences upstream of the putative CAAT boxes and exhibited significant divergence in all other portions of the gene. Conserved sequences in the 5'-flanking regions of these genes were identified and discussed in light of their potential regulatory role. The derived primary sequences of all three glutelin genomic clones showed significant homology to the legume 11 S storage proteins indicating a common gene origin. A comparison of the derived glutelin primary sequences showed that mutations were clustered in three peptide regions. One peptide region corresponded to the highly mutable hypervariable region of legume 11 S storage proteins, a potential target area for protein modification. Expression studies indicated that glutelin mRNA transcripts are differentially accumulated during endosperm development. Promoters of Gt2 and Gt3 were functional as they direct transient expression of chloramphenicol acetyltransferase in cultured plant cells.

Amino Acid Sequence↗