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H Y Yang

Publications and source records attributed to H Y Yang.

At least 19 recordsLinked to original sources
PubMed1992

Release of neuropeptide FF (FLFQPQRF-NH2) from rat spinal cord.

Neuropeptide FF (FLFQPQRF-NH2), originally isolated from bovine brain, is an FMRF-NH2-like peptide with morphine-modulating activity. Neuropeptide FF (NPFF) is highly localized in the dorsal spinal cords where there are also specific NPFF binding sites. Furthermore, there have been studies indicating that NPFF may participate in the regulation of pain threshold in the spinal cord. However, whether NPFF can be released from the spinal cord is not known. The present experiments, using an in vitro superfusion of an isolated whole rat spinal cord, demonstrated that high concentrations of KCl or substance P caused a release of NPFF immunoreactive material (IR) from the spinal cord into the perfusion medium in a calcium-dependent manner. Substance P (1-11) also produced a detectable release of NPFF-IR in vivo although the response was quite variable. The released NPFF-IR was analyzed by an HPLC study and found to consist of NPFF and other minor immunoreactive peptides. Further studies with substance P-related peptides showed that the in vitro release of NPFF-IR could also be induced by substance P (1-7) but not by [pGlu5,Me-Phe8,Sar9]-substance P (5-11) or substance K. These results suggest that the specific substance P receptor (SP-N), which is recognized by both substance P (1-11) and substance P (1-7) rather than the tachykinin receptor, is involved in NPFF secretion from the spinal cord. In view of the role of substance P (1-11) and substance P (1-7) in sensory transmission, the results of this study further support the role of NPFF in the modulation of antinociception in the spinal cord.

Amino Acid Sequence↗
PubMed1992

Distinct developmental subtypes of cultured non-stellate rat astrocytes distinguished by a new glial intermediate filament-associated protein.

The nature and tissue origin of cultured non-stellate astrocytes have not been defined. On the basis of immunofluorescence microscopy using multiple double-labeling with antibodies to glial fibrillary acidic protein (GFAP), vimentin, and the recently identified intermediate filament-associated protein (IFAP)-70/280kD, four distinct astrocytic subtypes were definable in neonatal rat brain astrocytes in culture. All of these were of the non-stellate type on the basis of morphology. Similar examination of developing rat cerebral cortex identified these same subtypes as distinct differentiation states of astrocytes. These findings indicate that the parallel developmental events can be studied in vitro.

Animals↗
PubMed1992

Colchicine-sensitive and colchicine-insensitive intermediate filament systems distinguished by a new intermediate filament-associated protein, IFAP-70/280 kD.

A monoclonal antibody was produced, using as antigen a BHK-21 cytoskeletal preparation enriched in intermediate filaments (IF) and their associated proteins. This antibody reacted exclusively with a reproducible set of 70-280 kD polypeptides present in minor quantities in this preparation, as detected by immunoblot analysis. Based upon several criteria, this immunologically related group of polypeptides was designated as IFAP-70/280 kD (IF-Associated Protein): (1) it co-isolated with IF in vitro, (2) it co-localized (by both immunofluorescence and immunoelectron microscopy) with IF in situ in all stages of cell spreading, and (3) it segregated in vitro with the 54/55 kD (desmin/vimentin) structural IF subunit proteins of BHK cells through two cycles of in vitro disassembly/assembly. Immunogold labeling further localized IFAP-70/280 kD to regions of parallel or loosely bundled IF in situ, suggesting a role in regulating the supramolecular organization of IF. When this monoclonal antibody was used for double-label immunofluorescence observations of colchicine-treated BHK cells, it demonstrated the presence of colchicine-sensitive and colchicine-insensitive IF. Anti-IFAP-70/280 kD localized entirely to the drug-induced juxtanuclear IF cap, while a polyclonal antibody directed against the desmin/vimentin structural IF subunits and the previously characterized monoclonal anti-IFAP-300 kD [Yang et al., 1985; J. Cell Biol. 100:620] localized to both the juxtanuclear IF cap and a colchicine-insensitive IF network peripheral to the cap in the same cells. The colchicine-insensitive IF pattern often exhibited similarities to that observed for the actin-based stress fiber system, suggesting that stress fiber association may be an additional factor in IF organization.

Animals↗
PubMed1992

Two-locus mitochondrial and nuclear gene models for mitochondrial disorders.

Stimulated by a large pedigree with a cochlear form of deafness, for which we considered a two-locus mitochondrial and nuclear gene model, we have extended the classic methods of segregation analysis to these classes of two-locus disorders. Based on the unique maternal transmission pattern of the mitochondria, we demonstrate that utilization of the maternal line pedigree allows us to simplify the various two-locus mitochondrial models to "one nuclear locus" models. Classifying the nuclear families into different independent groups by the mother's phenotypes allows us to estimate the nuclear gene frequency in one group and to use this estimate as the expected value to test the fitness of the model on the other group. In addition, if we restrict the analysis to specific subsets of the mating type(s), we can also test the model on specific groups of nuclear families without estimating the gene frequency. Goodness-of-fit tests can be performed on pooled sibship data as well as individual sibship data. These methods of analysis should assume increasing importance as more disorders with features of mitochondrial inheritance are identified.

Cell Nucleus↗
PubMed1992

Antigenic cross-reactions among immunoglobulin of diverse vertebrates (elasmobranchs to man) detected using xenoantisera.

1. Antisera raised in rabbits and goats against intact immunoglobulins or their constituent light and heavy chains from man, mouse and the galapagos shark (Carcharhinus galapagenesis) were tested for their reactivity with immunoglobulins of elasmobranchs, other lower vertebrates and eutherian and prototherian mammals. 2. Xenoantisera directed against human heavy chain isotypes allowed the serological identification of IgM and IgG immunoglobulins in the echidna (Tachyglossus aculeatus), a monotreme which is one of the most primitive species of extant mammals. 3. The antisera to heavy chains reacted to varying degrees with purified immunoglobulins of non-mammalian species, including the chicken, teleost fish and elasmobranchs in a fashion that was specific for immunoglobulins, but was not related to defined human isotypic markers. 4. The reactions of some antisera seem to skip species known to possess homologous immunoglobulins. 5. Antisera directed against isotypic markers of human kappa and lambda light chains reacted with shark light chains in a manner that was specific for light chain determinants but was not isotype-related. 6. Antisera directed against heavy chains of either sharks or mammals reacted with heavy chains, but not with light chains of diverse species. 7. A rabbit antiserum specific for shark light chain reacted with human and murine monoclonal lambda chains and with two synthetic peptides corresponding to human V lambda Fr3 and Fr4 sequences. 8. These results establish that a variety of antigenic markers including conformational and linear determinants can be shared among immunoglobulins of vertebrates species that had an ancestral divergence more than 400 million years ago.

Amino Acid Sequence↗
PubMed1992

Adenosine dephosphorylates myosin light chain in primary cultures of vascular smooth muscle cells from normotensive and spontaneously hypertensive rats.

OBJECTIVE: The aim was to determine whether vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) respond differently to adenosine than those from normotensive Wistar-Kyoto (WKY) rats. DESIGN: Confluent primary cultures of VSMC derived from SHR and WKY aorta and mesenteric arteries and cerebral arteries were used. The effect of adenosine upon cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) formation and the phosphorylation of myosin light chain (MLC) was studied. METHODS: MLC phosphorylation was estimated by subjecting VSMC extracts incubated with 32P to gel electrophoresis, followed by autoradiography and laser densitometry. cAMP and cGMP levels were measured by radioimmunoassay. RESULTS: Baseline MLC phosphorylation levels were not significantly different in SHR and WKY VSMC. Adenosine caused dephosphorylation of MLC in a time- and dose-dependent manner. A maximal response of approximately 40% below control values was observed 5 min after addition of 10(-5) mol/l adenosine in SHR and WKY VSMC with no significant difference between the two strains. The maximally effective concentration of 10(-5) mol/l adenosine evoked increases in both cAMP and cGMP in VSMC from SHR and WKY rats to the same degree. CONCLUSION: We conclude that the overall ability of VSMC to relax, as evidenced by a marked decrease in MLC phosphorylation in response to adenosine, is unaltered in SHR.

Adenosine↗
PubMed1992

Distinct roles for the two cGATA-1 finger domains.

We have generated and analyzed by functional assays mutations of the chicken erythroid transcription factor GATA-1. The cGATA-1 protein contains two related finger domains highly conserved across species and characteristic of the family of GATA-binding factors. We find that mutations in the C-terminal finger or adjacent basic region abolish sequence-specific DNA binding, confirming that this region constitutes a novel DNA-binding domain sufficient to recognize the consensus WGATAR motif. At least three separate regions outside of this finger II domain contribute in a cooperative manner to the trans-activation potential of the protein. As expected from previous results analyzing the mouse homolog, we find that the N-terminal finger plays a role in DNA binding by affecting the stability of the DNA-protein complex. In addition, we find mutations of finger I subtly altered in DNA-binding function which greatly diminish trans-activation. Our results support the notion that the GATA-1 protein must be positioned precisely on the GATA cis element to enable the activation of target genes.

Animals↗
PubMed1992

Sensorineural deafness inherited as a tissue specific mitochondrial disorder.

We present here a large Israeli-Arab kindred with hereditary deafness. In this family 55 deaf subjects (29M, 26F), who are otherwise healthy, have been identified and traced back five generations to one common female ancestor. The deafness is progressive in nature, usually presenting in infancy and childhood. Audiometry on six deaf and seven unaffected subjects was consistent with severe to profound sensorineural hearing loss. Based on formal family segregation analysis, the inheritance of deafness in this family closely fits the expectation of a two locus model owing to the simultaneous mutation of a mitochondrial gene and an autosomal recessive gene. Thus, this disorder appears to have the unusual features of being an inherited tissue specific mitochondrial disease and apparently requiring the homozygous presence of a nuclear gene for clinical expression. Most importantly, this disorder presents a unique opportunity to investigate the molecular basis of hereditary non-syndromic deafness and normal hearing.

Adult↗
PubMed1992

[Study on localization of cystic fluid antigen of Cysticercus cellulosae using McAb-IGSS].

A study was undertaken on the localization of specific combination of McAb against cystic fluid antigen of Cysticercus cellulosae by immunogold silver staining method (IGSS). It was shown that the combination sites of McAb F3 were distinct in the frozen and paraffin sections of Cysticercus cellulosae. The black granules in the bladder walls presented double-layer distribution and those in the scolex folded sites concentrated into pieces. The combination sites of McAb labeled by IGSS against cystic fluid antigen of Cysticercus cellulosae were consistent with the distribution of the cell layers of Cysticercus cellulosae. The sections in the control group had scarce and irregular distribution, which could be differentiated distinctly from those in the experimental group.

Animals↗
PubMed1991

IgG from neuropeptide FF antiserum reverses morphine tolerance in the rat.

Previous studies suggest that neuropeptide FF (NPFF) plays a role in opiate dependence and subsequent abstinence syndrome. The present study assessed the role of NPFF in opiate tolerance. Third ventricular injection of IgG from NPFF antiserum restored the analgesic response to i.c.v. morphine in morphine-tolerant rats (radiant heat tail flick test). IgG from control serum failed to produce this effect. In opiate-naive rats, however, the same treatment with IgG from NPFF antiserum did not affect the analgesic response to i.c.v. morphine. Thus, immunoneutralization of NPFF appears to selectively restore morphine sensitivity in opiate-tolerant animals. These results support the hypothesis that endogenous NPFF contributes to opiate tolerance.

Amino Acid Sequence↗
PubMed1991

Organogenesis-stage cytochrome P450 isoforms: utilization of PCR for detection of CYP1A1 mRNA in rat conceptal tissues.

Utilizing the reverse transcriptase-linked polymerase chain reaction, we analyzed the capacity of three groups of rat conceptal tissues to express cytochrome P4501A1 (CYP1A1) mRNA during the dysmorphogenesis-sensitive stage of organogenesis. The visceral yolk sac, ectoplacental cone and embryo proper each were investigated on day 12 of gestation with and without prior exposure in utero to 3-methylcholanthrene as inducing agent. With two sets of discriminating oligonucleotide primers, definitive, reproducible signals were detectable only in tissues from 3-methylcholanthrene preexposed conceptuses. Signals of highest intensity were observed with visceral yolk sac tissues and signals of lowest intensity were observed with tissues of the embryo per se. Specificities of the amplified cDNAs were verified using Southern blotting with hybridization to an internal oligonucleotide probe. The results indicate that organogenesis-stage conceptual tissues of the rat will express CYP1A1 mRNA in response to environmental transregulating agents.

Animals↗
PubMed1991

Ontogeny of the F8Famide-like (morphine-modulating) peptides in the central nervous system of rats.

FLFQPQRF-NH2 (F8Famide; FMRFamide-like peptide; morphine-modulating peptide) is a peptide isolated from bovine brain. It has some opiate analgesia modulating effects. In an adult rat central nervous system, F8Famide-like immunoreactivity is found in high concentrations in the posterior pituitary, hypothalamus, pons, medulla, and dorsal spinal cord. By using immunohistochemistry and radioimmunoassay, we studied the development of the F8Famide-immunoreactive system in the rat central nervous system during the ontogeny. F8Famide-immoreactive fibers and terminals first appeared in the median eminence on the twentieth embryonal day. Postnatally the F8Famide-immunoreactive system developed rapidly both in the brain and spinal cord, the immunoreactive structures having an adultlike distribution by the age of 1 week. A transient increase of the F8Famide-immunoreactive material was observed during the third and fourth postnatal weeks. By the age of 4 weeks, the F8Famide-containing neuronal system was adultlike both in distribution and quantity. The results suggest that the F8Famide-like peptides may act as neurotransmitters or neuromodulators from the time of their appearance in the brain and spinal cord. The early appearance and the distribution of the F8Famide-like immunoreactivity suggest that these peptides may participate, in addition to nociceptive mechanisms, in the regulation of blood pressure, feeding behaviour, and endocrine functions.

Amino Acid Sequence↗
PubMed1991

cAMP-dependent regulation of P450-catalyzed dealkylation in rat conceptal tissues.

Exposures of cultured whole rat conceptuses to varying concentrations of dibutyryl cyclic AMP or isobutylmethylxanthine, alone or in combination, resulted in significant increases in rates of cytochrome P450-dependent depentylation of pentoxyphenoxazone in cell-free preparations. Lesser increases in rates of debenzylation of benzyloxyphenoxazone were also observed. In cultured whole conceptuses, basal depentylase and debenzylase activities in the visceral yolk sac were approximately sixfold higher than in the embryo. The ectoplacental cone and decidual tissues exhibited no detectable depentylase activity. Only the visceral yolk sac exhibited increased depentylase activity in response to dibutyryl cyclic AMP and isobutylmethylxanthine. Inhibitory antibodies raised against adult hepatic P450s IIB1, IIC11, and IA1 failed to significantly inhibit the yolk sac depentylase activities of noncultured conceptuses. The results suggested that the conceptal depentylation reaction may be catalyzed by a unique P450 isoform(s) that is not expressed during adult life.

1-Methyl-3-isobutylxanthine↗
PubMed1991

Cytochrome P450-dependent bioactivation of prodysmorphogens in cultured conceptuses.

These investigations were undertaken to determine the extent to which tissues of cultured rat conceptuses contain cytochrome P450 isoforms in sufficient quantities to significantly influence the capacity of certain chemicals to elicit dysmorphogenic effects in vitro. Investigations with highly sensitive probe substrates/inhibitors and with immunologic methods enabled the detection of at least four separate P450 isoforms in tissues of the visceral yolk sac, ectoplacental cone, and embryo proper. One of the isoforms was identified as P450IA1 and was found to be inducible by polycyclic aromatic hydrocarbons in all three tissues. Other isoforms exhibited properties differing from characterized adult rat hepatic isoforms. Each of the isoforms was detectable in conceptuses on gestational days 10, 11, 12, and 14 and was present in the highest concentrations in the visceral yolk sac. Conceptal P450IA1 catalyzed the conversion of dysmorphogenically inactive 2-acetylaminofluorene to 7-hydroxy-2-acetylaminofluorene, a proximate dysmorphogen. Investigations with microinjections suggested that visceral yolk sac hydroxylation was largely responsible for the bioactivation reaction in vitro. The same isoform exhibited no capacity to influence the dysmorphogenic activity of cyclophosphamide. The results demonstrated that tissues of cultured rat conceptuses may contain P450 isoforms in sufficient amounts to markedly influence the dysmorphogenic activity of substrates of the corresponding isoforms.

Animals↗
PubMed1991

Angiotensin II induced phosphorylation of myosin light chain in vascular smooth muscle cells from spontaneously hypertensive and normotensive rats.

STUDY OBJECTIVE: The aim was to determine the changes in the phosphorylation of myosin light chain induced by angiotensin II in cultured vascular smooth muscle cells derived from normotensive (WKY) and spontaneously hypertensive rats (SHR). DESIGN: Extracts of vascular smooth muscle cells incubated with [32P]orthophosphoric acid were subjected to 4M urea-SDS electrophoresis, followed by autoradiography and laser densitometry. EXPERIMENTAL MATERIAL: Confluent primary cultures of vascular smooth muscle cells from aorta, superior mesenteric arteries and cerebral arteries were used. MEASUREMENTS AND MAIN RESULTS: The basal myosin light chain phosphorylation of SHR did not differ significantly from that of WKY. Stimulation with 1 nM angiotensin II increased incorporation of 32P into the myosin light chain, which peaked at 4 min and then slowly declined until 15 min. Exposure to angiotensin II (0.001-10 nM) for 4 min evoked a dose dependent increase in the phosphorylation of myosin light chain with a maximal response 40-45% above basal values. No significant differences in the response to angiotensin II were detected between cells derived from the two strains. Saralasin, a specific angiotensin II antagonist, did not affect the basal phosphorylation of myosin light chain but completely abolished the effect of angiotensin II. CONCLUSIONS: Angiotensin II enhances the phosphorylation of the myosin light chain from vascular smooth muscle cells in aorta, mesenteric arteries, and cerebral arteries, but there are no differences in response between SHR and WKY.

Angiotensin II↗