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Biomedical subjects

J H Han

Publications and source records attributed to J H Han.

124 records · Page 7Linked to original sources
PubMed1987

Menstrual blood loss, iron nutriture, and the effects of Alza-T IPCS 52, T-Cu 220C and Lippes Loop D in Korean women.

The upper normal limit of menstrual blood loss (MBL) associated with iron deficiency, and the change of MBL and length of time necessary for development of iron depletion after IUD insertion in 193 healthy Korean women were studied. The mean MBL was 33.4 +or- 23.4 (SD) ml and the variation of MBL in different marital, age, and parity groups showed no statistical significance except for the higher values in young married women. Serum ferritin concentration was markedly decreased in women showing MBL above 40 ml and the frequency of subjects with serum ferritin below anemia criteria were increased in women showing MBL above 50 ml. Other parameters for assessing the iron status showed no significant difference in a different MBL range. The mean MBL in women fitted with an Alza-T IPCS 52 was significantly decreased 3 months after insertion, but the increases in hemoglobin and serum ferritin levels were statistically significant at 12 months postinsertion. The mean MBL in other IUD groups was remarkably increased at 1 month in T-Cu 220C users and between months 1-12 in Lippes Loop D users. Significant decreases in serum ferritin levels were observed at 6 and 12 months in both groups.

Age Factors↗
PubMed1987

The role of insulin mediators in regulation of cAMP and lipogenesis as well as in diabetes.

Plasma membranes prepared from pig, mouse and rat liver incubated with insulin resulted in the release of at least two insulin chemical mediators. These mediators, identified as fractions 1 and 3, were found to inhibit cAMP level in response to lipolytic hormone and forskolin and to enhance lipogenesis in adipocytes of rat. Fractions 1 and 3 have been estimated to have molecular weights of 3700-4000 and 1000-1500 dalton, respectively. This initial report will focus on fraction 1. Interestingly, liver membranes from diabetic animals were found not to release mediators in the presence of insulin. However, following in vivo treatment of diabetic animals with insulin, the liver membranes appeared to restore its ability in generating chemical mediators in response to insulin.

Adipose Tissue↗
PubMed1986

Selective expression of rat pancreatic genes during embryonic development.

We present the developmental profiles of the mRNAs of 10 selectively expressed pancreatic exocrine genes and of insulin. The mRNA profiles fall into three related classes, but each profile is in some respect unique. The data on gene expression suggest there are four developmental states of the exocrine pancreas: early morphogenesis and low-level gene expression (the protodifferentiated state), the embryonic differentiated state, a modulated state in neonatal animals, and the adult differentiated state. Each state is characterized by distinct ratios of the exocrine mRNAs and presumably involves a distinct regulatory transition. This complex differentiative program must involve multiple regulatory molecules.

Amylases↗
PubMed1986

Multiple transcription start sites, DNase I-hypersensitive sites, and an opposite-strand exon in the 5' region of the CHO dhfr gene.

Transcription of the 26-kilobase (kb) dihydrofolate reductase (dhfr) gene in CHO cells is initiated at two sites: a major site (approximately 85% of the dhfr mRNA) at -63 relative to the translation start and a minor site (approximately 15%) at -107. Transcription also occurs from the opposite DNA strand in the dhfr 5' region, with a probable initiation site at approximately -195 relative to the dhfr translation start. A 4-kb polyadenylated RNA that is derived from the opposite-strand transcription increases threefold in abundance after serum starvation of CHO cells for 24 h. dhfr mRNA levels do not change during this time. The first dhfr exon lies within a 1-kb genomic region marked by exceptionally high G + C content and lack of DNA methylation. This region also includes a 214-base-pair (bp) exon for the opposite-strand transcript and five of the six DNase I-hypersensitive sites identified at the dhfr locus. Analysis of the DNA sequences of hamster, human (M. Chen, T. Shimada, A. D. Moulton, A. Cline, R. K. Humphries, J. Maizel, and A. W. Nienhuis, J. Biol. Chem. 259:3933-3943, 1984), and mouse (M. McGrogan, C. C. Simonsen, D. T. Smouse, P. J. Farnham, and R. T. Schimke, J. Biol. Chem. 260:2307-2314, 1985) dhfr genes reveals the presence of a 29-bp unit that is conserved 45 to 49 bp upstream of major and minor dhfr transcription start sites. This unit follows the consensus: GRGGCGGTGGCCTNNNNTGTCRCAARTRGGTR. The 5' part of the 29-bp unit contains a GC box that agrees with the GGGCGG consensus-binding site for the RNA polymerase II transcription factor Sp1 (D. Gidoni, W. A. Dynan, and R. Tjian, Nature (London) 312:409-413, 1984). Each of the three mammalian dhfr genes has several G-rich GC boxes proximal to the major dhfr transcription start site and several GC boxes of the opposite orientation (C rich) in a distal region about 500 bp upstream.

Animals↗
PubMed1984

Screening recombinant phage M13 plaques with RNA probes; a one-step procedure which identifies clones containing either of the complementary DNA strands.

We describe a method for detecting specific DNA sequences cloned in M13 phage vectors, based on the procedure of Woo (in Wu, R., Methods in Enzymology, Vol. 68, Academic Press, New York, 1979, pp. 389-395). M13 plaques are adsorbed to a nitrocellulose filter that has been pre-saturated with bacteria. The filter is incubated on an agar plate to amplify the phage; the DNA is alkali-denatured and then hybridized with a radioactive RNA probe. Unlike standard procedures, this method detects and distinguishes M13 plaques containing phage particles which harbor either the coding or non-coding (RNA-like) DNA strand, when single-stranded RNA is used as probe. We have optimized this procedure with M13 clones containing mouse histidine tRNA gene sequences and have used it to determine the sequence of both strands of a mouse glycine tRNA gene.

Animals↗
PubMed1984

Structure and evolution of mammalian tRNA genes: sequence of a mouse tRNAiMet gene, the 5'-flanking region of which is homologous to a human gene.

From a recombinant lambda phage, we have determined a 317-bp sequence containing a mouse tRNAiMet gene. The coding region is precisely homologous to mammalian tRNAiMet if post-transcriptional modifications (including addition of the 3'-terminal CCA) are not considered. The gene does not contain introns and has a typical RNA polymerase III termination site in the 3'-flanking region. It is transcribed by RNA polymerase III in the HeLa cell S-100 system in vitro. Notably, the 5'-flanking region of the mouse tRNAiMet gene shares a "patchwork" pattern of homology with one of the human tRNAiMet genes of Santos and Zasloff [Cell 23 (1981) 699-710]. The 5'-flanking regions of the two genes contain strings of nucleotides, 6 to 32 bp in length, the homology of which is 76-100%. These are separated by short strings of unrelated nucleotides. This is one of the first examples of tRNA genes containing homologous 5'-flanking regions isolated from distantly related mammals. We also report a novel method for constructing deletion mutants of sequences cloned in M13 vectors.

Animals↗
PubMed1984

Antihypertensive activities of phenyl aminoethyl sulfides, a class of synthetic substrates for dopamine beta-hydroxylase.

Four sulfur-containing analogues of phenylpropylamine were synthesized and evaluated as substrates for dopamine beta-hydroxylase (DBH) and monoamine oxidase (MAO). All four phenyl aminoethyl sulfides were shown to be good substrates for DBH whereas only the two analogues not possessing a methyl group alpha to the terminal amino group were substrates for MAO. All four analogues were tested for acute antihypertensive activity in an animal model for hypertension, the spontaneously hypertensive rat (SHR). Two of the analogues, both of which should partition readily across the blood-brain barrier, did not appreciably reduce systemic blood pressure in the 6-h testing period. However, the two analogues that were designed to be relatively restricted to peripheral sites of action caused a dramatic drop in blood pressure in SHR of 25% within 1-1.5-h postinjection, with the analogue designed to be both restricted to the periphery and MAO inactive, causing a more prolonged antihypertensive activity.

Animals↗
PubMed1983

Using iodinated single-stranded M13 probes to facilitate rapid DNA sequence analysis--nucleotide sequence of a mouse lysine tRNA gene.

From a recombinant lambda phage, we have determined a 387 bp sequence containing a mouse lysine tRNA gene. The putative lys tRNA (anticodon UUU) differs from rabbit liver lys tRNA at five positions. The flanking regions of the mouse gene are not generally homologous to published human and Drosophila lys tRNA genes. However, the mouse gene contains a 14 bp region comprising 13 A-T base pairs, 30-44 bp from the 5' end of the coding region. Cognate A-T rich regions are present in human and Drosophila genes. The coding region is flanked by two 11 bp direct repeats, similar to those associated with alu family sequences. The sequence was determined by a "walking" protocol that employs, as a novel feature, iodinated single-stranded M13 probes to identify M13 subclones which contain sequences partially overlapping and contiguous to an initially determined sequence. The probes can also be used to screen lambda phage and in Southern and dot blot experiments.

Animals↗
PubMed1982

Isolation and nucleotide sequence of a mouse histidine tRNA gene.

We have sequenced a 1307 base pair mouse genomic DNA fragment which contains a histidine tRNA gene. The sequence of the putative mouse histidine tRNA differs from the published sequence of sheep liver histidine tRNA by a single base change in the D-loop. It does not contain an unpaired 5' terminal G residue, as reported for Drosophila and sheep histidine tRNAs. The gene does not contain introns. The 3' flanking region contains a typical RNA polymerase III termination site of 6 consecutive T residues. 523 residues after the 3' end of the his tRNA coding region, the mouse DNA contains a sequence 72% homologous to part of the consensus sequence of the B1 (alu) family.

Animals↗
PubMed1981

[Electrophoretic study on the changes of serum protein fractions in Korean women--the effects of age, oral contraceptive, and intrauterine contraceptive device (author's transl)].

The serum levels of total protein, albumin, and electrophoretic fractions from 610 Korean women, 21-50 years, were measured to determine their relation to age, and the effects of oral contraceptives (OCs) (Norinyl), and Lippes Loop IUD. In normal women, total protein and albumin concentrations significantly decreased with age. Alpha2 and gamma globulin concentrations were decreased after the age of 40, but the statistical significance was low. Significant decreases in total protein and albumin concentrations were observed in OC and IUD users, and rapid decrease in total protein was observed in OC users rather than in IUD users. Beta globulin was slightly increased in both groups, and gamma globulin was decreased in OC users. No significant changes in alpha1 and alpha2 globulin concentrations were noted in either group.

Age Factors↗
PubMedDate not supplied

Effects of phenyl-2-aminoethyl sulfide, a novel dopamine-beta-hydroxylase substrate, on the cardiovascular system of the anesthetized dog.

In previous work we have established that phenyl-2-aminoethyl sulfide (PAES) is a novel substrate for dopamine-beta-hydroxylase (DBH) which is stereospecifically oxygenated by the enzyme to the corresponding sulfoxide, (S)-phenyl-2-aminoethyl sulfoxide (PAESO). We now report that PAES possesses very little, if any, direct adrenergic agonist activity, but exhibits indirect sympathomimetic activity at relatively high doses (approximately 4 mg/kg). This assertion, that PAES is a new indirect sympathomimetic, is supported by our finding that pretreatment with cocaine completely abolishes the sympathomimetic activity of PAES. Furthermore, the effects of PAES are diminished with consecutive administration. In addition to its indirect sympathomimetic activity, we have also observed that PAES infusion almost completely blocks the reflex response elicited by hydralazine, a direct vasodilator. In contrast, we have found that PAESO possesses neither direct nor indirect sympathomimetic activity at doses as high as 6 mg/kg. Since PAES should be readily converted in vivo into PAESO, the implications of these findings in terms of potential antihypertensive action of PAES are discussed.

Animals↗
PubMedDate not supplied

Overexpression of and RNA interference with the CCAAT enhancer-binding protein on long-term facilitation of Aplysia sensory to motor synapses.

In the marine mollusk Aplysia, the CCAAT/enhancer-binding protein, ApC/EBP, serves as an immediate early gene in the consolidation of long-term facilitation in the synaptic connection between the sensory and motor neurons of the gill-withdrawal reflex. To further examine the role of ApC/EBP as a molecular switch of a stable form of long-term memory, we cloned the full-length coding regions of two alternatively spliced forms, the short and long form of ApC/EBP. Overexpression of each isoform by DNA microinjection resulted in a l6-fold increase in the expression of the coinjected luciferase reporter gene driven by an ERE promoter. In addition, when we overexpressed ApC/EBP in Aplysia sensory neurons, we found that the application of a single pulse of 5-HT that normally induced only short-term facilitation now induced long-term facilitation. Conversely, when we attempted to block the synthesis of native ApC/EBP by microinjecting double-strand RNA or antisense RNA, we blocked long-term facilitation in a sequence-specific manner. These data support the idea that ApC/EBP is both necessary and sufficient to consolidate short-term memory into long-term memory. Furthermore, our results suggest that this double-strand RNA interference provides a powerful tool in the study of the genes functioning in learning and memory in Aplysia by specifically inhibiting both the constitutive and induced expression of the genes.

Amino Acid Sequence↗
PubMedDate not supplied

Lymphatic delivery and pharmacokinetics of methotrexate after intramuscular injection of differently charged liposome-entrapped methotrexate to rats.

The lymph node targeting ability and pharmacokinetics of methotrexate (MTX) after intramuscular (i.m.) injection of differently charged liposome-entrapped [3H]MTX to rats were evaluated using [3H]MTX as a tracer. Neutral liposomes were prepared with a mixture of phosphatidylcholine, cholesterol and alpha-tocopherol (8:4:0.1, molar ratio). Positively and negatively charged liposomes were also prepared by incorporation of stearylamine (8:4:0.1, molar ratio) and dicetylphosphate (8:4:0.1:1, molar ratio) into neutral liposomes respectively. The encapsulation efficiency (as expressed in terms of radioactivity) in liposomes was increased as alpha-tocopherol was incorporated into the lipid bilayer. The disappearance of [3H]MTX from the i.m. injection site was rapid and essentially complete after 30 min. On the other hand, the disappearance of radioactivity of liposome-entrapped [3H]MTX was much slower when compared to free drug. The area under the drug concentration-time curve (AUC) of liposome-entrapped [3H]MTX in lymph nodes was significantly increased when compared to free [3H]MTX. It suggested that liposomes injected by the i.m. route entered into the lymphatics and only drug released from liposomes diffused directly into the systematic circulation. The liposome-entrapped [3H]MTX by i.m. route was markedly localized in the lymph nodes. The concentration of MTX-equivalents in regional lymph node after i.m. injection of liposome-entrapped [3H]MTX was > 100-350 fold higher when compared to the plasma concentration. These values are more than 10-20 fold higher compared to the i.m. injection of free [3H]MTX. The positively charged liposomes were more localized in lymph nodes compared to neutral and negatively charged ones. While liposomes injected by i.v. route were localized in liver, spleen and lung compared to free [3H]MTX, it was evident that i.m. administration of liposomes resulted in enhanced localization of MTX in the lymphatic system but decreased deposition in kidney, liver and other non-targeting tissues compared to free [3H]MTX. The targeting ability and carrier properties of liposome-entrapped anticancer drugs with varying surface charge, lipid compositions and route of administration are of significant importance to alter biodistribution in chemotherapy.

Animals↗
PubMedDate not supplied

Sequence of precursor polyprotein gene (segment A) of infectious bursal disease viruses isolated in Korea.

The coding regions of segment A of two recent Korean very virulent (vv) infectious bursal disease virus (IBDV) isolates (KK1 and KSH) and one atypical IBDV isolate (K310) were amplified by reverse transcriptase-polymerase chain reaction, sequenced, and compared with published sequences for IBDV. The overall amino acid sequence similarity of the KK1 and KSH strains compared with foreign vvIBDV strains was between 97.43% and 98.02%. The KK1 and KSH strains, like vvIBDV strains, share unique amino acid residues at positions 222(A), 256(I), 294(I), and 299(S). The sequence of K310 strain was markedly different from other IBDV strains. The K310 strain had 12, 2, and 1 unique amino acid substitutions in the VP2 hypervariable region, VP4, and VP3 gene, respectively, and 3 of 12 substitutions in a VP2 hypervariable region were found in two hydrophilic regions known to be involved in antigenic determination. Also, the K310 strain had 222(S) and 254(S), which were found in variant IBDV strains. The SWSASGS heptapeptide is conserved in all Korean IBDV isolates. By phylogenetic analysis, KK1 and KSH were categorized in one group with foreign vvIBDV isolates, but K310 isolate was categorized in a separate group that was differentiated from the other IBDV strains compared. The K310 strain seemed to be evolved from a separate lineage of IBDV strain.

Amino Acid Substitution↗