PubMed Health⌕ Search

Biomedical subjects

S E Lee

Publications and source records attributed to S E Lee.

16 recordsLinked to original sources
PubMed1992

Quantitation of preproenkephalin mRNA levels in brain regions from male Fischer rats following chronic cocaine treatment using a recently developed solution hybridization assay.

Quantitative solution hybridization assays were used to determine the picogram amounts of preproenkephalin mRNA (PPenk mRNA) and the microgram quanities of total rat RNA in extracts of eight brain regions from rats which had received three daily intraperitoneal injections of cocaine (10 or 30 mg/kg/day) or saline for 14 days. The young adult male Fischer rats were sacrificed 30 min after the final injection. The highest density of PPenk mRNA (pg PPenk mRNA/micrograms total cellular RNA) was found in extracts of striatum (34.08 +/- 1.79 pg/micrograms for 11 saline-treated rats), followed by extracts of nucleus accumbens (10.08 +/- 0.81 pg/micrograms), and extracts of hypothalamus (2.99 +/- 0.31 pg/micrograms). Extracts of frontal cortex (1.78 +/- 0.24 pg/micrograms), pituitary (1.39 +/- 0.08 pg/micrograms), central grey (1.31 +/- 0.16 pg/micrograms), and cerebellum (1.24 +/- 0.09 pg/micrograms) had intermediate values. Extracts of hippocampus (0.53 +/- 0.03 pg/micrograms) had the lowest density. No significant differences were found among the treatment groups in any brain area investigated. Therefore, chronic cocaine treatment as administered in this protocol did not alter expression of the gene encoding proenkephalin.

Animals↗
PubMed1991

Penile hemangioma: US and MR imaging demonstration.

A case of a penile hemangioma is reported. The mass had hypoechogenicity on ultrasonography (US) and high signal intensity on T2-weighted magnetic resonance (MR) image. MR images clearly demonstrated the extent of the lesion, especially deep extension into the corpus cavernosum.

Adult↗
PubMed1991

Flow-cytometric analysis of testes in infertile men: a comparison of the ploidy to routine histopathologic study.

DNA flow-cytometric analysis was performed on the testicular needle biopsies of 25 infertile men with azoospermia or oligozoospermia to evaluate the ability of DNA histograms in order to detect and quantify alterations in spermatogenesis. Concomitant histopathologic study was performed on the tissues from needle biopsy. In contrast to difficulty in quantifying spermatogenesis in histopathologic examination, flow-cytometric analysis revealed characteristic ploidy patterns in the relative proportions of haploid (1 n), diploid (2 n) and tetraploid (4 n) cells corresponding to the histopathologic appearances of normal spermatogenesis, hypospermatogenesis, maturation arrest and aspermatogenesis. Findings evaluated with flow cytometry were well correlated with those from routine histopathologic study. In 21 of these patients (84%) there was concordance between histopathologic and flow-cytometric diagnoses. However, in 4 patients (16%) there was discordance between two diagnostic modalities. In conclusion, DNA flow cytometry of testicular biopsies was a reproducible, objective and quantitative approach in evaluating infertile men, and it is a promising method to investigate spermatogenesis in an outpatient clinic in lieu of formal testicular histopathologic study.

DNA↗
PubMed1991

Identification of mutagenic site of c-H-ras oncogene damaged by N-acetoxyacetylaminofluorene(AAAF).

A molecularly cloned human cellular H-ras (c-H-ras) oncogene(pbc N1 plasmid) was treated with N-acetoxyacetylaminofluorene (AAAF) in vitro and subcloned into E.coli. This was done to identify the mutational changes at specific codons of the gene. Guanine nucleotides were identified as the major AAAF binding site of the DNA adduct formed. Base changes in codons 12 and 61 were determined by the analysis of restriction fragment length polymorphism (RFLP) and site specific oligonucleotide hybridization. RFLP was observed due to the loss of the Hpall recognition site at codon 11 and 12 of AAAF-treated c-H-ras gene. Hybridization of AAAF treated c-H-ras with 32P-labeled oligonucleotide probes for the mutant alleles of codon 61 showed no substitutions at codon 61. From these results, it is assumed that AAAF treatment in vitro caused mutation at codon 12 but not at codon 61 of the c-H-ras oncogene and that codon 12 is the primary target of mutation by AAAF.

Acetoxyacetylaminofluorene↗
PubMed1991

Branched-chain fatty acid requirement for avermectin production by a mutant of Streptomyces avermitilis lacking branched-chain 2-oxo acid dehydrogenase activity.

The eight natural avermectins produced by Streptomyces avermitilis have the carbon skeleton of either isobutyric or S-2-methylbutyric acid incorporated into their structures. A mutant of S. avermitilis has been isolated that contains no functional branched-chain 2-oxo acid dehydrogenase activity. The mutant, in contrast to its parent, is unable to grow with isoleucine, valine and leucine as carbon sources. In medium lacking both S(+)-2-methylbutyric and isobutyric acid, the mutant is also incapable of making the natural avermectins, while supplementation with either one of these compounds restores production of the corresponding four natural avermectins. These facts indicate that in S. avermitilis the branched-chain 2-oxo acid dehydrogenase enzyme functions not only to catabolize the cellular branched-chain amino acids in order to meet energy and growth requirements but also to provide the small branched-chain organic acid precursor molecules necessary for avermectin biosynthesis. Supplementation of the mutant strain with R(-)-2-methylbutyric acid yields novel isomeric avermectins unseen in the (unsupplemented) wild-type strain. It was also concluded that acetate and propionate production by branched-chain 2-oxo acid degradation is not absolutely essential for avermectin production.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1990

Expression of human plasminogen activator inhibitor type-1 (PAI-1) in Escherichia coli as a soluble protein comprised of active and latent forms. Isolation and crystallization of latent PAI-1.

Expression of human recombinant plasminogen activator inhibitor type-1 (PAI-1) in Escherichia coli has led to crystallization of 'latent' PAI-1. Cleavage with restriction endonucleases of a cDNA clone encoding PAI-1 yielded an 1127 base pair fragment encoding residues 2-376 of the 379 amino acid serpin. Synthetic DNA linkers were ligated to the 5' and 3' ends of the subclone to add an initiation codon and restore the full coding sequence, and the resulting semisynthetic gene was incorporated into an expression plasmid, pPAIST-7, under the control of the E. coli trp promoter. Transformation of E. coli GE81 with pPAIST-7 led to expression of unglycosylated PAI-1. Lysates of expression cultures contained PAI-1 activity and PAI-1 protein with the predicted Mr. Unglycosylated PAI-1 from E. coli exhibited characteristic properties of authentic PAI-1: (1) it was recovered in both active and inactive (latent) forms; (2) its activity declined during incubation at 37 degrees C; (3) latent PAI-1 was activated by treatment with 4 M guanidine hydrochloride; (4) reactivated PAI-1 formed a detergent-stable complex with tissue plasminogen activator. Latent PAI-1 accounted for more than 85% of PAI-1 in cell lysates and was purified by ammonium sulfate fractionation, anion-exchange chromatography and hydrophobic interaction chromatography. The purified latent PAI-1 was crystallized.

Amino Acids↗
PubMed1990

Transfection of mouse cells with thymidine kinase gene of herpes simplex virus.

A mouse cell line (LP1-1) was established from the murine L cells deficient in thymidine kinase (L-M(TK-] by prolonged selective culture on the hypoxanthine-aminopterine-thymidine (HAT) medium following transfection with the thymidine kinase gene of herpes simplex virus type-I (HSVTK). Southern blot analysis has shown that the viral TK gene was integrated into one of the chromosomal loci by a single copy. From this established cell line, the 5-bromo-2-deoxyuridine (BrdU) resistant revertant was brought out at a frequency of 1 x 10(-6) and from these BrdU resistant revertants (LP1BU), one out of 1 x 10(5) cells could return to the HAT-resistant phenotype. The established LP1-1 cell line showed a typical biphasic nature of DNA synthesis as determined by the 3H-thymidine incorporation test. The activity of thymidine kinase was shown to be equivalent to that of the DNA polymerase-alpha when the whole nuclear fraction or the nuclear matrix were used for examination. These results indicate that the transfected viral TK gene can be expressed under the normal cell-cycle regulation and its gene product can act as a component of the multienzyme complex which is responsible for DNA replication.

Animals↗
PubMed1990

De-epithelialized scrotal flap in repair of urethrocutaneous fistula and hypospadias.

Eight cases of closure of urethrocutaneous fistula and 15 cases of urethroplasty for hypospadias are reviewed. Most of the fistulas were present in the penoscrotal level. Fistula and hypospadias opening were closed by re-enforcement using a de-epithelialized scrotal skin flap. Of 8 patients with fistula, there was no recurrence, and 3 procedures were performed without urinary diversion or urethral stent. Of 15 patients with hypospadias, there was no fistula formation in the original urethral opening area but a fistula distal to the original urethral opening developed in 3 patients. This technique is satisfactory in repairing complicated as well as noncomplicated urethrocutaneous fistula and can be done without urinary diversion or urethral stent. It appears to be useful in reducing fistula formation following urethroplasty in hypospadias or urethral fistula repair.

Humans↗
PubMed1990

Flow cytometric assessment of deoxyribonucleic acid content in renal adenocarcinoma: does ploidy status enhance prognostic stratification over stage alone?

Flow cytometry was used to analyze deparaffinized primary renal cell carcinoma specimens from 106 patients to evaluate deoxyribonucleic acid ploidy as a predictor of disease progression and survival. Of these specimens 62 (58%) demonstrated aneuploid stem lines: 30 (48%) of these were tetraploid aneuploid while 32 were nontetraploid aneuploid. Two or more specimens were analyzed from a single primary tumor in 17 patients and heterogeneity of ploidy status was observed in 5 (30%). Specimens of the primary tumor, and regional and/or distant metastases from 11 patients were analyzed; 5 (45%) demonstrated discordance between the ploidy of the primary and the metastatic site. A significant correlation was noted between the presence of aneuploid stem lines and high stage disease (p equals 0.004) but there was no significant correlation between ploidy status and tumor grade. Although there was a significant difference (p equals 0.037) in the incidence of disease progression in patients with diploid tumors (13%) versus those with aneuploid tumors (35%) in the total population, and Kaplan-Meier disease-specific survival curves demonstrated a survival advantage for patients with diploid tumors in the total population, no clear survival advantage was demonstrated for evaluable patients with diploid tumors when controlled for tumor, nodes and metastases stage. In conclusion, the heterogeneity of ploidy status in primary renal cell carcinoma, the high incidence of disease progression in patients with diploid primary tumors and the lack of a clearly demonstrable stage-independent impact of ploidy on prognosis currently would not support widespread clinical application of ploidy status of the primary tumor in the management of individual patients with renal cell carcinoma.

Adult↗
PubMed1990

Surgical procedures in the management of Takayasu's arteritis.

Takayasu's arteritis is an inflammatory arteriopathy that often progresses to obliteration of multiple large arteries. Variable results have been reported after medical and surgical management. Twenty female patients with Takayasu's arteritis were treated from 1973 to 1989. Eleven (55%) patients had hypertension. Upper or lower extremity ischemia was present in 12 (60%) patients and cerebrovascular insufficiency in seven (35%). Nine patients initially managed with corticosteroids had no improvement in signs or symptoms of arterial insufficiency. Eleven patients had 16 vascular procedures for the following indications: renovascular hypertension (6), extremity ischemia (5), cerebrovascular insufficiency (2), dilation ascending aorta with aortic insufficiency (1), thoracic aortic aneurysm (1), abdominal aortic aneurysm (1). Procedures included aortorenal bypass (5), carotid-subclavian, axillary, or brachial bypass (4), aorto-carotid bypass (2), aneurysm resection (2), supra-celiac aorto-femoral bypass (1), ascending aorta/aortic valve replacement (1), and nephrectomy (1). Clinical improvement occurred in all patients. There were no operative deaths. All are alive at a mean follow-up of 5.75 years (6 months to 16 years). Revision of the initial reconstruction has been required for recurrent renovascular hypertension in one patient and extremity ischemia in another. The other nine patients remain symptomatically improved. Symptomatic Takayasu's arteritis frequently requires arterial reconstruction. Symptomatic improvement and excellent long-term graft patency can be expected after arterial reconstruction.

Adolescent↗
PubMed1990

Studies on rat liver nuclear DNA damaged by chemical carcinogen (3'-Me DAB) and AP DNA endonuclease. I. Purification and some properties of AP DNA endonucleases in rat liver chromatin.

Three kinds of apurinic/apyrimidinic (AP) DNA endonuclease, APcI, APcII, APcIII, were purified from rat liver chromatin through 1M KCl extraction, DEAE-trisacryl ion exchange chromatography. Sephadex G-150 gel filtration and AP DNA cellulose affinity chromatography. Activities of the purified APcI, APcII and APcIII were 62.5, 83.3 and 52.0 EU/mg of protein, respectively. Molecular weights of APcI, APcII and APcIII, each consisting of a single polypeptide, were 30,000, 42,000 and 13,000, and isoelectric points of them were 7.2, 6.3 and 6.2, respectively. Three enzymes showed different substrate specificities; APcI acted only on AP DNA, and APcII acted on both AP DNA and UV DNA, while APcIII acted on 3'-methyl-4-monomethylaminoazobenzene (3'-Me MAB) DNA adduct as well as AP DNA and UV DNA. These results indicate that three kinds of AP DNA endonuclease present in rat liver chromatin have structural and functional diversities.

Animals↗
PubMed1990

Studies on rat liver nuclear DNA damaged by chemical carcinogen (3'-Me DAB) and AP DNA endonuclease. II. Kinetic properties of AP DNA endonucleases in rat liver chromatin.

An experiment was designed to investigate the reaction mechanism of AP (apurinic or apyrimidinic) DNA endonucleases (APcI, APcII, APcIII) purified from rat liver chromatin. Sulfhydryl compounds (2-mercaptoethanol, dithiothreitol) brought about optimal activities of AP DNA endonucleases and N-ethylmaleimide or HgCl2 inhibited the enzyme activities, indicating the presence of sulfhydryl group at or near the active sites of the enzymes. Mg2+ was essential and 4mM of Mg2+ was sufficient for the optimal activities of AP DNA endonucleases. Km values of APcI, APcII and APcIII for the substrate (E. coli chromosomal AP DNA) were 0.53, 0.27 and 0.36 microM AP sites, respectively. AMP was the most potent inhibitor among adenine nucleotides tested and the inhibition was uncompetitive with respective to the substrate. The Ki values of APcI, APcII and APcIII were 0.35, 0.54 and 0.41mM, respectively. The degree of nick translation of AP DNAs nicked by APcI, APcII and APcIII with Klenow fragment in the presence and absence of T4 polynucleotide kinase or alkaline phosphatase were the same, suggesting that all 3 AP DNA endonucleases excise the phosphodiester bond of AP DNA strand to release 3-hydroxyl nucleotides and 5-phosphomonoester nucleotides.

Animals↗
PubMed1978

Spatial distribution of colonic carcinoma.

During the past several decades, there has been a shift in the distribution of colorectal cancer toward the right side, with an increase in colon lesions on the right side and a marked decrease in rectal lesions. In 1,009 cases studied between 1966 and 1977, this change in distribution pattern is illustrated. A revision of widespread current concepts of colonic cancer detection is indicated.

Animals↗
PubMed1977

Emphysematous pyelonephritis.

We herein describe 2 cases of emphysematous pyelonephritis, which can be added to the 42 cases previously reported. Both female patients were diabetic and had Escherichia coli infections. Both had ureteral obstruction and underwent nephrectomy to survive septic and/or azotemic crises. Timely surgical intervention after unsuccessful antibiotics and conventional medical measurements is life-saving.

Adult↗