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Biomedical subjects

Y Lee

Publications and source records attributed to Y Lee.

At least 541 records · Page 30Linked to original sources
PubMedDate not supplied

RNases in ColE1 DNA metabolism.

ColE1 DNA replication is initiated by RNA II and inhibited by RNA I. Control of the replication occurs through the interaction between RNA I and RNA II. Therefore, RNases involved in the metabolism of RNA I and RNA II are expected to play a key role in the control of the ColE1 plasmid replication. RNase H, RNase E, RNase III, RNase P, and polynucleotide phosphorylase carry out the many specific reactions of the RNA metabolism.

Base Sequence↗
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Balloon dilatation of intrahepatic biliary strictures for percutaneous extraction of residual intrahepatic stones.

Intrahepatic ductal strictures in cholangiohepatitis present an obstacle to successful removal of retained ductal stones via T-tube tracts. We studied the effectiveness of stricture dilatation for stone removal. Fifteen patients with intrahepatic gallstones retained behind strictures underwent balloon dilatation of their strictures to allow stone extraction. All had prior surgical T-tube placement allowing percutaneous access. Balloon dilatation was successful in reducing or eliminating strictures in 86.7% (13 of 15 patients), and complete stone extraction after the successful dilatation was possible in 76.9% (10 of 13 patients). The reasons for failure were impacted stones and acute ductal angulation which prevented passage of catheters. It is concluded that balloon dilatation of intrahepatic biliary strictures is an effective adjunct for extraction of intrahepatic biliary calculi associated with recurrent pyogenic cholangiohepatitis.

Adult↗
PubMedDate not supplied

GRF analogs and fragments: correlation between receptor binding, activity and structure.

GH-releasing activity in vitro was directly correlated with GRF receptor binding affinity for all hGRF analogs examined. hGRF(1-29)-NH2 analogs with Ala15-substitution (for Gly15) displayed 4-5 times higher affinity for the GRF receptor relative to hGRF(1-44)-NH2. Replacement of Gly15 with Sar15 resulted in a dramatic loss of activity and receptor binding. The present data supports the proposal that Ala15-substitution increases receptor affinity, and hence potency, due to increased amphiphilic alpha-helical interactions. Fragments of hGRF, representative of DPP-IV and trypsin-like cleavage, are inactive as a consequence of greatly diminished GRF receptor binding. These results provide a comprehensive analysis of the structural features required for both GRF receptor binding and activation.

Animals↗
PubMedDate not supplied

Synthesis and biological activity of novel C-terminal-extended and biotinylated growth hormone-releasing factor (GRF) analogs.

A series of novel hGRF(1-29)-NH2 analogs were synthesized and biotinylated. The immunological and biological activities of these analogs were then characterized. To distance the biotin moiety from the putative bioactive core, a C-terminal spacer arm consisting of -Gly-Gly-Cys-NH2 (-GGC) was added to hGRF(1-29)-NH2 (hGRF29) and analogs, with subsequent biotinylation performed at the cysteine residue. Neither addition of the C-terminal spacer arm nor biotinylation affected affinity of these analogs for GRF antibody. Relative to hGRF(1-44)-NH2 (hGRF44: potency = 1.0), the biotinylated analogs were equipotent in vitro to their nonbiotinylated, parent compounds: [desNH2Tyr1,D-Ala2,Ala15]hGRF29-GGC-(tpBiocyt in)-NH2 (4.7) = [Ala15]hGRF29-GGC-(tpBiocytin)-NH2 (3.9) greater than hGRF29-GGC-(tpBiocytin)-NH2 (0.8). Based upon cumulative GH release data in vivo (0-60 min postinjection), [desNH2Tyr1,D-Ala2,Ala15]hGRF29-GGC-(tpBiocyt in)-NH2, [Ala15]hGRF29-GGC-(tpBiocytin)-NH2, and hGRF29-GGC-(tpBiocytin)-NH2 displayed 8.6, 5.5, and 0.8 times, respectively, the potency of hGRF44. These in vivo potency values were not significantly different from the corresponding parent compounds (i.e., with or without the C-terminal spacer arm). In summary, biotinylated hGRF analogs have been developed that retain full immunoreactivity and potent bioactivity (in vitro and in vivo), thus permitting their use in GRF receptor isolation, ELISA, and histochemical procedures.

Amino Acid Sequence↗
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Nonsurgical management of epidural hematoma in neonates.

We successfully treated 4 neonates with epidural hematoma by nonsurgical methods. In 3 of these infants, epidural hematoma was complicated by cephalohematoma and skull fracture; however, the epidural hematoma disappeared after aspiration of the dark red blood in the cephalohematoma, resulting in complete recovery without sequelae. In the remaining infant, epidural hematoma was complicated by intraventricular and subarachnoid hemorrhage and disseminated intravascular coagulation; the patient was successfully treated by conservative therapy, including exchange transfusion and repeated lumbar puncture with only mild motor difficulties remaining. Some patients with neonatal epidural hematomas can be managed by nonsurgical, conservative procedures, including cephalohematoma aspiration.

Hematoma, Epidural, Cranial↗
PubMedDate not supplied

Breast tumors associated with nipple discharge. Correlation of findings on galactography and sonography.

To compare the specific information provided by ultrasound (US) and galactography and to appreciate the clinical applicability of US as a primary diagnostic method for breast tumors associated with nipple discharge, a comparative study of each method in 15 patients with ductal tumors of the breast was performed. To evaluate the smallest anatomical unit of the lactiferous system demonstrable by US, 30 patients with normal lactating breasts were examined prospectively. The smallest anatomical ductal unit that could be evaluated with US in the normal lactating breast was the terminal duct lobular unit (TDLU). US is superior to galactography in detecting masses smaller than 0.5 cm or lesions involving multiple ducts. Galactography is better for visualizing the duct system and detecting calcification. In conclusion, US serves as a primary noninvasive diagnostic tool in patients with clinically suspicious breast tumor associated with bloody nipple discharge, but galactography also should be done in specific circumstances.

Adult↗
PubMedDate not supplied

Activation of CD14 on circulating monocytes in patients with acute coronary syndrome.

BACKGROUND: Increasing evidence supports the involvement of inflammation in acute phase of coronary artery diseases. METHODS: We analyzed the status of activation of inflammatory cells in 38 patients with acute coronary syndrome, 14 stable angina patients, and 19 control subjects by flow-cytometry. Expression levels of CD14 and the percentage of HLA-DR(+) T-lymphocytes were used as markers of monocyte and T-lymphocytes activation, respectively. RESULTS: The expression of CD14 on monocytes in acute coronary syndrome patients (mean fluorescence intensity+/-S.D.=158.1+/-77.1) was increased significantly in comparison to control subjects (57.1+/-8.0) and the stable angina group (63.6+/-22.0) (P<0.0001 for both). A significantly higher percentage of HLA-DR positive T-lymphocytes (20.4+/-9.0 vs. 12.7+/-3.7%, P<0.01) was observed in acute coronary syndrome patients in comparison to control subjects. Incubation of whole blood cells with bacterial lipopolysaccharide resulted in a 2.4-fold higher secretion of tumor necrosis factor-alpha in acute coronary syndrome patients than in control subjects (P<0.05). When these markers of activation were measured in acute coronary syndrome patients 6 weeks after medical treatment, a significant reduction both in monocytic CD14 expression and percentage of HLA-DR positive T-lymphocytes (P<0.05 for both) was observed. DISCUSSION: We observed markedly increased levels of monocytic CD14 expression in ACS patients, which appear to indicate the activated status of monocytes and hyper-responsiveness to external stimuli. The CD14 expression levels decreased as the patients were treated, indicating that the expression of CD14 accurately represents the activation status of monocytes during the acute phase of coronary artery diseases.

Aged↗
PubMedDate not supplied

The effect of pentoxifylline on current perception thresholds in patients with diabetic sensory neuropathy.

Diabetic peripheral neuropathy is a common, painful, and disabling condition that is known to occur by two mechanisms: hyperglycemia and arterial blood flow occlusion. Pentoxifylline (Trental) functions by improving erythrocyte flexibility in blood vessels, which could increase the delivery of oxygen to occluded nerve vessels. This 1-year clinical trial was aimed at ascertaining the effects of pentoxifylline on diabetic sensory neuropathy. Fifty patients with type I or II diabetes were evaluated in a randomized, double-blind, parallel group and placebo-controlled study. Pentoxifylline effectiveness was evaluated by measuring glycated hemoglobin, blood pressure and current perception threshold (CPT). The CPT results showed no statistically significant effect of pentoxifylline on mean nerve sensory perception thresholds in ankle and toe at 5, 250 and 2000 Hz. There were no significant changes in glycated hemoglobin or in systolic and diastolic blood pressure during the trial. Thus, glycated hemoglobin and blood pressure did not explain the lack of pentoxifylline effect on diabetic neuropathy. In conclusion, pentoxifylline appears not to add benefits to the clinical treatment of diabetic sensory neuropathy of the lower extremity.

Adult↗
PubMedDate not supplied

Inconsistency of fetal trophoblast cells in first trimester maternal peripheral blood prevents non-invasive fetal testing using this cell target.

We have investigated whether maternal peripheral blood from the first trimester of pregnancy is a reliable source of identifiable trophoblast cells. The cells were enriched from 30 ml of venous blood, with multiple antibodies shown previously to enrich trophoblasts and a new cocktail based on known trophoblast surface features. Three different magnetic solid phases were tested to enrich trophoblasts, and both positive and negative cell enrichment strategies were examined. The cells were identified as trophoblast by morphology coupled with immunocytochemistry to co-localize cytokeratin with one of three IGF-II, PAI-1 or hPLH proteins or by in-situ hybridization with a mixture of 50 oligos directed to eight different expressed genes, alpha-HCG, IGF-II, PAI-1, HASH2, hPLH, p57(KIP2), PP5, H-19. While these tools worked beautifully in chorionic villi cell/sprout preparations and tissue sections, we could not detect and identify any trophoblasts in maternal peripheral blood even if the maternal peripheral blood was drawn 5-20 min following termination of pregnancy or from individuals maintaining the pregnancy. Based on our own experience and that of some reports in the literature, trophoblasts do not appear to be a viable candidate for fetal screening using maternal peripheral blood as the source. It is important to note that while trophoblast deportation is a biological phenomenon that has been described repeatable, they do not provide a means to perform prenatal genetic diagnosis.

Antibodies↗