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Biomedical subjects

S Lee

Publications and source records attributed to S Lee.

At least 901 records · Page 50Linked to original sources
PubMed1996

Apparent heparin resistance form elevated factor VIII in a patient with postoperative deep venous thrombosis. A case report.

BACKGROUND: During the puerperium, heparin levels, rather than the adjusted partial thromboplastin time test, can be used to identify heparin resistance and guide heparin therapy. CASE: A patient receiving heparin for deep venous thrombosis had artifactual resistance to heparin, with a short adjusted partial thromboplastin time due to elevation of factor VIII. Heparin assay revealed a heparin level above the therapeutic range. CONCLUSION: Direct measurement of heparin concentration and factor VIII activity should be performed when heparin resistance is suspected.

Adult↗
PubMed1996

[Social support exchange and quality of life among the Korean elderly in a rural area].

This study focuses on the influence of social support exchange through informal networks on Quality of Life (QOL) of the elderly. A total of 740 community residents aged 60 and over living in a rural area in Korea were interviewed from July 12 to July 15, 1993. Subjects were asked about the frequency of providing and receiving support to and from their spouse, children, and friends (24 items). The interview also included two QOL items (morale and life satisfaction) as well as instrumental ADL (five items), sex, age, education, and living arrangement. ANOVA showed that providing support to their children was strongly related to high morale score in female subjects. The elderly providing support to their friends were more likely to score high in morale. Analysis showed that the female elderly with greater support from their husbands had higher life satisfaction score. On the other hand, the male elderly group who provided support to their spouses but did not receive equal support in return from their spouses had low life satisfaction score. Providing support to their children was found to relate to high life satisfaction in both males and females, while receiving support from their children improved life satisfaction only in the females. Overall, the elderly group who exchanged support frequently with their spouses, children and friends showed the highest QOL score than any other group. These findings highlight the importance of supportive behavior by the elderly in order to improve their QOL.

Aged↗
PubMed1996

Determination of trimethoprim and sulphadoxine residues in porcine tissues and plasma.

Healthy gilts and market-ready hogs were administered a single intramuscular (IM) injection of Borgal, a commercial formulation of trimethoprim-sulfadoxine (TMP-SDX), once or twice daily. The objectives were to determine if a newly-developed high-performance liquid chromatographic (HPLC) method would be suitable for measuring the residual concentrations of TMP in the plasma of these live animals, and to determine if the administration of this veterinary drug would leave measurable residues in their plasma and tissues at slaughter. Plasma and tissue concentrations of SDX and TMP from these animals were determined over a period of 14 d using thin-layer chromatography/densitometry (TLCD), and the newly-developed HPLC method, respectively. The lowest detectable limit (LDL) for SDX in plasma and tissue was 20 ppb by TLCD. The HPLC method had a LDL of 5 ppb for TMP in plasma and tissue. Both methods were then used to provide baseline data on the absorption and depletion of TMP and SDX from these healthy animals. It was observed that both TMP and SDX were readily absorbed into the blood and tissues, but TMP was eliminated much faster than SDX. No TMP residues were detected in the plasma of any of the gilts at and beyond 21 h after drug administration. Also, no TMP residues were detected in the plasma of any of the market-ready hogs 24 h after drug administration at either the label dose or twice the label dose. Sulfadoxine residues at concentrations above the maximum residue limit (MRL) of 100 ppb were, however, detected in the plasma, muscle, kidney, liver, and injection sites of hogs slaughtered 1 and 3 d after a single IM administration at the label dose. Although SDX residues were still detectable in the lungs, kidney, liver and plasma of some hogs 10 d after administration of the label dose and twice the label dose, these were below the MRL. Postmortem examination revealed necrosis and inflammation at the injection sites, but no visible deposits of the injected drug.

Animals↗
PubMed1996

The leaking esophagus: CT patterns of esophageal rupture, perforation, and fistulization.

Esophageal perforation can be a catastrophic event for a patient regardless of the etiology of the perforation. Contrast esophagrams can typically diagnose an esophageal perforation if the clinical symptoms or history suggest the diagnosis. Often, however, the clinical features are atypical and a CT scan is performed early in the patient's workup. It is, therefore, essential to recognize the CT features seen in esophageal perforation. The various etiologies and CT findings of esophageal perforation are reviewed in this article. The CT abnormalities include extraluminal air, periesophageal fluid, esophageal thickening, and extraluminal contrast. These CT findings may be the first clue to the correct diagnosis of esophageal perforation.

Esophageal Fistula↗
PubMed1995

Systemic endotoxin increases steady-state gene expression of hypothalamic nitric oxide synthase: comparison with corticotropin-releasing factor and vasopressin gene transcripts.

The enzyme responsible for nitric oxide (NO) formation, NO synthase (NOS), is found in hypothalamic neurons that control ACTH secretion. This led to the hypothesis that brain NO may modulate the response of the hypothalamic-pituitary (HP) axis to various stimuli. We tested this hypothesis by measuring changes in constitutive (c) NOS mRNA levels in the hypothalamus of rats systemically injected with endotoxin, a lipopolysaccharide (LPS) that releases endogenous cytokines, and analyzed these results in the context of the appearance of ACTH-releasing secretagogues such as corticotropin-releasing factor (CRF) and vasopressin (VP), as well as CRF receptors type A (CRF-RA). We purposefully chose doses of LPS thought to only minimally disrupt the blood-brain barrier and not be accompanied by an endotoxin shock, so that the results we obtained did not primarily stem from abnormal passage of compounds into the brain, or non-specific stress. Three to four hours following LPS injection (100 micrograms/kg, i.v.), cNOS mRNA levels increased in the paraventricular nucleus (PVN) of the hypothalamus. LPS treatment also upregulated PVN CRF gene transcription (measured by CRF heteronuclear RNA) and increased steady-state gene expression of the immediate early genes (IEG) c-fos and NGFI-B, with the first changes noted 1-2 h after treatment. Transcripts of CRF receptors type A were present in the hypothalamus 6 h after endotoxin treatment. On the other hand, no alterations in cytoplasmic VP mRNA levels were noted in rats injected with LPS. Because the dose of LPS we used stimulates ACTH secretion within 30 min, our results suggest that systemic LPS acts first within the median eminence, where it stimulates peptidic nerve terminals. Neuronal activation of hypothalamic cell bodies takes place later, and whether this phenomenon is due to the production of brain neurotransmitters and/or cytokines, or whether it primarily results from increased demand on the synthetic machinery, remains to be established. These studies extend prior work showing that systemic LPS increases the neuronal activity of hypothalamic regions known for their involvement in the responses of the HP axis, and bring forth two important additional points. First, increases in CRF primary nuclear transcripts are delayed with regard to the temporal release of ACTH. This suggests, though it does not demonstrate, that under the experimental conditions we used, the first site of action of LPS is the median eminence. Second, the observation of increased cNOS gene expression following LPS treatment, and the presence of this enzyme in neurons that regulate ACTH secretion, bring support to the hypothesis that this gas plays an important function in mediating the HP axis response to an immune challenge.

Adrenocorticotropic Hormone↗
PubMed1995

Aspartyl-tRNA synthetase of the hyperthermophilic archaeon Pyrococcus sp. KOD1 has a chimerical structure of eukaryotic and bacterial enzymes.

The aspartyl-tRNA synthetase (AspRS)-encoding gene from the archaeon, Pyrococcus sp. KOD1 (KOD1), was cloned and sequenced, and expressed in Escherichia coli. The purified AspRS possessed an aminoacyation activity for tRNA extracted from KOD1. Analysis of the deduced amino-acid sequence (438 aa, 50,893 Da) revealed that the AspRS of KOD1 is a chimerical protein of bacteria and eukarya. Regional analysis showed high sequence similarity to higher eukaryotic enzymes in the central and C-terminal regions which are important for catalytic activity of the enzyme. In contrast, the N-terminal portion exhibits bacterial features and does not possess the higher eukaryotic sequence which is involved in high molecular weight (HMW) complex formation. These results suggest that archaeon AspRS has a eukaryotic-type catalytic mechanism without forming the HMW complex. This is the first example which shows that an archaeal protein possesses eukaryotic and bacterial features.

Amino Acid Sequence↗
PubMed1995

Structural differences in the cerebral cortex of healthy female and male subjects: a magnetic resonance imaging study.

There are both reproductive and nonreproductive behavioral differences between men and women. Brain regions involved in determining sexual behavior have been reported to differ between the sexes. Nonreproductive, cognitive functional differences between sexes might be reflected in higher-order cortical structural dimorphisms, which have not previously been studied. We hypothesized that cortical regions involved in verbal behavior (which is sexually dimorphic) would differ between sexes. Using magnetic resonance imaging, we assessed gray matter volumes in several cortical regions in 17 women and 43 men. Women had 23.2% (dorsolateral prefrontal cortex) and 12.8% (superior temporal gyrus) greater gray matter percentages (corrected for overall brain size and age) than men in a language-related cortical region, but not in a more visuospatially related cortical region. These data seem to establish sexually dimorphic structural differences in the cerebral cortex, consistent with prior cerebral blood flow reports.

Adult↗
PubMed1995

The immunomodulatory effect of leflunomide in rat cardiac allotransplantation.

Leflunomide, a novel immunosuppressant, has been the subject of recent preclinical studies using solid organ allo- and xenotransplantation models. The objectives of this study were to evaluate the efficacy and toxicity of leflunomide using a rat cardiac allotransplant model in two different strain combinations (DA x PVG and DA x Lew). Leflunomide, at doses ranging between 5 and 30 mg/kg, prolonged graft survival in both strain combinations as effectively as CsA and FK506 1 mg/kg (P < 0.05). A dose-dependent effect was seen only after a longer treatment course. When ongoing rejection was intercepted early (postoperative day 2), 5 mg/kg was as effective as 1 mg/kg FK506 (P > 0.05) but was inferior to CsA in the DA x PVG combination (P < 0.05). However, in the DA x Lew combination, leflunomide was equally as efficacious as 15 mg/kg CsA and 1 mg/kg FK506 (P > 0.05). If ongoing rejection was treated at postoperative day 4, 10 mg/kg leflunomide was not only as effective as 15 mg/kg CsA and 1 mg/kg FK506, but demonstrated a dose-dependent increase in graft survival in both strain combinations. The toxicity of leflunomide at doses of especially 5-20 mg/kg was minimal in comparison to therapeutic doses of CsA and FK506 using body weight and biochemical parameters of renal and liver function. These in vivo observations convincingly show leflunomide to be equally as potent an immunosuppressant as CsA and FK506 in transplant rejection. It is also well tolerated on long-term administration and, by virtue of this fact, is a potentially suitable candidate for clinical transplantation.

Animals↗
PubMed1995

Structural organization and genetic localization of the human bone morphogenetic protein 1/mammalian tolloid gene.

Bone morphogenetic protein 1 (BMP1) is a putative protease purified from extracts capable of inducing ectopic bone formation. A single mammalian gene apparently encodes alternatively spliced transcripts for BMP1, for a longer protein with a domain structure identical to that of the Drosophila dorsal-ventral patterning gene product tolloid (Tld), and for a third species of low abundance. Here we describe the organization of the 46-kb, 22-exon human BMP1/mTld gene that encodes these forms. Exons corresponding to each of the alternatively spliced transcripts are identified, and comparison with the Drosophila Tld gene reveals alignment of introns at only three positions. The major BMP1/mTld transcription start site is found only 706 bp downstream of the polyadenylation site of the SFTP2 surfactant gene, and a previously reported highly polymorphic CA repeat is found within the BMP1/mTld first intron. These two findings place the BMP1/mTld gene between markers D8S298 and D8S5 on the genetic map.

Alternative Splicing↗