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Biomedical subjects

H Y Yang

Publications and source records attributed to H Y Yang.

At least 73 records · Page 4Linked to original sources
PubMed1996

Presence of a 300-kDa intermediate-filament-associated protein (IFAP-300kDa) in bovine chromaffin cells.

Intermediate filaments (IFs) are cell-type-specific filaments that constitute a major part of the cellular cytoskeleton. Neurofilaments (NFs) are representative of a class of IFs which are excellent markers for neurons. NFs are also present in some cells of neural crest origin. A number of proteins have now been identified as being associated with IFs. Previously, a 300-kDa intermediate-filament-associated protein (IFAP-300kDa) was identified in baby hamster kidney cells (BHK-21). This IFAP is developmentally regulated and is not found in the adult CNS. To learn more about the expression of IFAP-300kDa, this study investigated the expression of IFAP-300kDa in neural-crest-derived chromaffin cells, both in situ and in vitro. Immunofluorescence localization of IFAP-300kDa in cryosections of bovine adrenal gland demonstrated IFAP-300kDa immunoreactivity in the dopamine-beta-hydroxylase-positive chromaffin cells of the adrenal medulla. When rounded chromaffin cells in culture were examined, double-label immunofluorescence microscopy revealed an IFAP-300kDa/NF-L-positive juxtanuclear aggregate. The plasma membrane was also IFAP-300kDa positive, but NF-L immunoreactivity was lacking. In cells which have spread under the influence of NGF, slender IFAP-300kDa-positive immunofluorescent strands were frequently seen radiating from a juxtanuclear area of immunoreactivity. Double-labeling revealed these filaments and juxtanuclear area to also be positive for NF-L immunoreactivity. The presence of IFAP-300kDa in situ and in vitro was further confirmed by immunoblot analysis. This study is the first demonstration of an IFAP in neuron-like cells located outside the central nervous system. In addition, these data indicate that the developmentally regulated IFAP-300kDa may persist in some cells of neural crest origin.

Adrenal Glands↗
PubMed1996

Susceptibility locus for inflammatory bowel disease on chromosome 16 has a role in Crohn's disease, but not in ulcerative colitis.

In the Western world, chronic inflammatory bowel disease (IBD) presents as two major clinical forms, Crohn's disease (CD) and ulcerative colitis (UC) [Targan, S.R. and Shanahan, F. (1994). In Retford, D.C (ed.), Inflammatory Bowel Disease: From Bench to Bedside. Williams and Wilkins, Baltimore]. Genetic epidemiological studies, the occurrence of rare syndromes associated with IBD, and animal models suggest that inherited factors play significant roles in the susceptibility to both forms of IBD [Yang, H.-Y. and Rotter, J.I. (1995) In Kirsner, J.B. and Shorter, R.G. (eds). Genetic Aspects of Idiopathic Inflammatory Bowel Disease. Williams and Wilkins, Baltimore, pp.301-331]. Recently, a genome-wide search on European families with multiple affected members with CD identified a putative susceptibility locus in the centromeric region of chromosome 16 [Hugot, J.-P. et al. (1996) Nature, 379, 821-823]. We have now tested this region in an independent set of US families, confirmed that this region is likely to contain a gene predisposing to CD, and further refined the chromosomal location of this gene. Most importantly with respect to this locus, our data also seem to indicate that there is heterogeneity both within the CD group, and between the CD and UC groups with respect to this locus. The susceptibility locus appears to be involved only in non-Jewish CD sibpairs and not in our Ashkenazi Jewish CD sibpairs. Additionally, we have tested sibpairs having either only UC or both UC and CD for involvement of this locus, and have found no evidence that this region predisposes to IBD in these patients.

Chromosome Mapping↗
PubMed1996

Retrospective survey of a link between cat and dog antigens and allergic conjuctivitis.

This retrospective 3-year study was designed to determine (a) which antigen positive patients were found in greater numbers, (b) whether the patients who were positive for cat or dog antigen-specific IgE were also positive for other antigens, and (c) whether the number of patients with allergic conjunctivitis increased during a particular time of the year. A total of 762 patients were diagnosed with allergic conjunctivitis including 107 cat-positive and/or dog-positive patients. Cat-positive patients were more prevalent than dog-positive patients, (p < 0.001). All but 2 patients were positive for other antigens, indicating a strong link between the animal antigens and other antigens. Cat and dog allergy increased in spring and early summer.

Adolescent↗
PubMed1996

A seroepidemiologic study of Chlamydia pneumoniae, Chlamydia trachomatis and Chlamydia psittaci in different populations on the mainland of China.

To evaluate and compare the prevalence of antibodies to 3 chlamydial species in various populations on the mainland of China, the MIF test was used to detect both serum IgG and IgM antibodies to these species in the normal population (n = 711), in poultry workers (n = 51), in female prostitutes (n = 106), in patients attending the sexually transmitted diseases clinic (n = 98), and in adult patients with pneumonia and bronchitis (n = 108). In the normal population, IgG antibodies against C. pneumoniae, C. trachomatis and C. psittaci were present in 61.5%, 9.3%, and 3.5%, respectively, and increasing with age. Prevalence and geometric mean titers (GMT) of IgG antibodies to C. trachomatis in prostitutes (54.7%) and female (55%), but not male (15.4%) sexually transmitted disease patients were significantly higher than in the normal adult female population. The prevalence indicating both previous and recent C. psittaci infections in poultry workers was no higher than in the others. The prevalence of IgG antibodies and GMT to C. pneumoniae in patients with pneumonia and bronchitis was not statistically higher than in the normal adult population. Evidence of cross-reactivities in the MIF test between different species was found in both prevalence and GMT. Serum IgM antibodies were usually absent in patients who met the serological criteria of recent C. pneumoniae infection, indicating that most of them could be considered as reinfections. On the basis of our survey, acute antibodies to C. pneumoniae by the MIF test, if they are detected, may be valuable in the diagnosis of recent C. pneumoniae infections.

Adolescent↗
PubMed1996

Q-switched ruby laser in the treatment of nevus of Ota.

The purpose of this study is to evaluate the efficacy of Q-switched ruby laser in the treatment of nevus of Ota, a pigmented lesion on the face. The Q-switched ruby laser has been shown to remove tattoos without scarring. With this in mind, the nevus of Ota with pigmented cells in the dermis could be effectively treated with Q-switched ruby laser. Eighty patients (19 men, and 61 women) with nevus of Ota on the face were enlisted to be tested in evaluating the efficiency of Q-switched ruby laser therapy. The age of patients ranged from 1 to 62 years. The energy fluence used varied from 6 to 8.5 J/cm2. Treatment intervals ranged from 4 to 16 weeks, and the number of treatment sessions varied between 1 to 9 visits. During a 2-year follow-up period, more than fifty percent removal of nevus-pigment was noted in 64 of the 80 patients. Transient hyperpigmentation was noted in 32 patients lasting for 2 to 6 months after treatment; transient hypopigmentation was seen in 3 cases which recovered within one year. No patients had permanent textural or pigmentary changes or scarring. Q-switched ruby laser therapy appears to be an effective and safe modality for the treatment of nevus of Ota.

Adolescent↗
PubMed1996

[Serological survey on mycoplasma infection among three populations in Yunnan Province].

Mycoplasma infection in both female and male genital tract has attracted attention recently. 636 infertile and sterile cases together with 284 women with IUDs and 113 women with genital inflammatory complications after artificial abortion were detected through indirect hemagglutination test for serological survey on the frequency of ureaplasma urealyticum (Uu) and mycoplasma hominis (Mh) infection. Some of them were detected through isolated culture at the same time. Among the 636 infertile and sterile cases, the results showed that the antibody positive rate to mycoplasma was 26.10%. Among women with IUD, the antibody positive rate was 32.39%. However, the antibody positives rates among women with IUD shorter than three months were significantly higher than those prior to and three to twelve months after insertion of IUD (P < 0.01). Among the 113 women after abortion, the positive rate was 46.02%. The positive rates of the three groups were significantly different from the control group (P < 0.001), and the antibody titers to mycoplasma were significantly higher than that of the control group. It is suggested that mycoplasma infection is one of the important causes for infertility and causing complication of genital inflammatory symptoms after abortion.

Adult↗
PubMed1996

Limbal autograft transplantation for recurrent and advanced pterygia.

BACKGROUND AND OBJECTIVE: This study was conducted to examine the usefulness of limbal autograft transplantation in the treatment of recurrent and advanced pterygia. PATIENTS AND METHODS: Eleven patients with recurrent and 16 with advanced pterygia (a total of 27 pterygia) were treated with limbal autograft transplantation. Once a pterygium had been excised, superior limbal tissue was taken with conjunctival flap and transferred to the excised area. RESULTS: All the grafts were planted promptly, and donor sites were re-epithelialized with no excessive scar tissue formation. Although slight recurrence was noted in 2 eyes (7.4%), subconjunctival tissue invasions were limited to less than 1 mm, and no further surgical interventions were needed. CONCLUSION: These results indicate that limbal autograft transplantation may be effective for the treatment of recurrent and advanced pterygia.

Adult↗
PubMed1996

Catalysis of the dealkylation/debenzylation of phenoxazone ethers by hemoglobin in the absence of peroxides: implications for investigations of embryonic biotransformation.

Investigations of catalysis of the O-dealkylation and O-debenzylation of phenoxazone (resorufin) ethers in human and rodent embryonic tissue homogenates indicated that, with few exceptions, each conceptal tissue investigated contained enzymes capable of catalyzing each of the reactions under study. All observable reactions exhibited NADPH dependence and strong inhibition by carbon monoxide, ketoconazole, alternate electron acceptors, and by hypoxic incubation conditions; but, they were not strongly inhibited by several other classical cytochrome P450 (P450) inhibitors. Cyanide, azide, superoxide dismutase/catalase, and glutathione/glutathione peroxidase each also failed to inhibit the reactions significantly. Subcellular fractionation experiments revealed that cytosolic fractions contained a preponderance of the observable monooxygenase activities. Attempts to identify components responsible for the cytosolic catalytic activity indicated that cytosolic nitric oxide synthases did not contribute significantly. Column fractionation of the cytosol indicated that significant catalytic activity coeluted with fractions containing hemoglobin (Hgb), and experiments with purified Hgb as enzyme source showed that Hgb would catalyze all reactions under study at very slow rates in the absence of added reductases or peroxides. Additions of either reductases or peroxides, however, resulted in marked increases in rates of Hgb-catalyzed reactions. Further investigations strongly suggested that virtually all dealkylation or debenzylation of phenoxazone ethers catalyzed by embryonic cytosolic fractions could be accounted for by the presence of Hgb in those fractions. Conceptal microsomal fractions, however, exhibited definitive, P450-dependent monooxygenase activities attributable to specific individual, identifiable P450 isoforms.

Animals↗
PubMed1995

Expression of functional cytochrome P4501A1 in human embryonic hepatic tissues during organogenesis.

Investigations with chemical inhibitors and with inhibitory antibodies specific for cytochrome P4501A-catalyzed ethoxyresorufin (ethoxyphenoxazone) O-deethylation and 2-acetylaminofluorene (N-2-fluorenylacetamide) ring hydroxylation indicated that cytochrome(s) P450 of the 1A subfamily was functionally expressed in human embryonic hepatic tissues at very early stages (days 50-60) of gestation. Lack of detectable capacity of hepatic microsomal enzymes to catalyze either N-hydroxylation of 2-acetylaminofluorene or O-demethylation of methoxyresorufin indicated that functional cytochrome P4501A2 is expressed minimally or negligibly in human embryonic hepatic tissues. By contrast, profound inhibition of the ring hydroxylation of 2-acetylaminofluorene and of the O-deethylation of ethoxyresorufin by 7,8-benzoflavone as well as by anti-cytochrome P4501A1 antibodies indicated the presence of significant levels of functional cytochrome P4501A1 in hepatic microsomes of human embryos. Using the reverse transcriptase-linked polymerase chain reaction with specific oligonucleotide primers, we also detected significant expression of cytochrome P4501A1 mRNA in human embryonic livers. Polymerase chain reaction amplification, cloning and sequencing of the corresponding cDNA provided evidence that the cytochrome P4501A1 mRNA expressed in human embryonic tissues was identical to that expressed in adult human tissues. The results of the study have important implications in terms of the embryotoxic effects of chemicals that are known to be substrates, inhibitors or inducers of cytochrome P4501A1 and to which pregnant women are exposed.

2-Acetylaminofluorene↗
PubMed1995

Homotypic interactions of chicken GATA-1 can mediate transcriptional activation.

We used a one-hybrid system to replace precisely the finger II chicken GATA-1 DNA-binding domain with the binding domain of bacterial repressor protein LexA. The LexA DNA-binding domain lacks amino acids that function for transcriptional activation, nuclear localization, or protein dimerization. This allowed us to analyze activities of GATA-1 sequences distinct from DNA binding. We found that strong transcriptional activating sequences that function independently of finger II are present in GATA-1. Sequences including finger I contain an independent nuclear localizing function. Our data are consistent with cooperative binding of two LexA-GATA-1 hybrid proteins on a palindromic operator. The sensitivity of our transcription assay provides the first evidence that GATA-1 can make homotypic interactions in vivo. The ability of a non-DNA-binding form of GATA-1 to activate gene expression by targeting to a bound GATA-1 derivative further supports the notion that GATA-1-GATA-1 interactions may have functional consequences. A coimmunoprecipitation assay was used to demonstrate that GATA-1 multimeric complexes form in solution by protein-protein interaction. The novel ability of GATA-1 to interact homotypically may be important for the formation of higher-order structures among distant regulatory elements that share binding sites for this transcription factor. We also used the system to test the ability of GATA-1 to interact heterotypically with other activators.

Amino Acid Sequence↗
PubMed1995

Direct sub-Tenon's ocular anesthesia for strabismus surgery.

We assessed the safety and effectiveness of sub-Tenon's anesthesia, a local anesthesia, for strabismus surgery. For 15 surgeries, we used anesthesia by sub-Tenon's infusion, followed by direct infusion through a transconjunctival route with a local anesthetic agent. We found the procedure was simple, it minimized complications compared with other techniques and was effective in achieving rapid anesthesia. With the ocular movement remaining, we checked eye position by the alternative cover-uncover test at the end of surgery. We obtained good eye position for all patients. This method leads to good results for strabismus surgery.

Adolescent↗
PubMed1995

Persistent epithelial defect following penetrating keratoplasty: an adverse effect of diclofenac eyedrops.

Association between the use of diclofenac sodium (DfNa) eyedrops and the development of a postkeratoplasty persistent epithelial defect (PED) of the cornea were studied. In 100 consecutive patients undergoing penetrating keratoplasty who had no limbal or conjunctival epithelial abnormalities, 12 (12.0%) developed PED (persistence of epithelial defect for > 8 days after keratoplasty) postoperatively. The use of DfNa eyedrops correlated significantly with the development of PED (p = 0.0001, chi-square test). DfNa eyedrops were used in 19 eyes postoperatively, eight of which (42.1%) showed signs of PED. The type of preservation media, preservation time, indications for keratoplasty, or the surgical procedures performed did not correlate with the development of PED. These results indicate that DfNa eyedrops are toxic to the corneal epithelium postkeratoplasty. The eyedrops should be used with great care in patients with disorders of the corneal epithelium.

Adult↗
PubMed1994

Induction in vitro and complete coding region sequence of cytochrome P4501A1 cDNA from cultured whole rat conceptuses during early organogenesis.

Exposures of cultured whole rat conceptuses during organogenesis to 3-methylcholanthrene (MC; 0.025-25 microM), 5,6-benzoflavone (BNF; 5-100 microM) or benz[a]anthracene (BA; 5-100 microM) were effected by placement of each of these "MC-type" inducing agents in the culture medium at the time of explantation on day 9.5 of gestation. Conceptuses were then cultured for 48 hr and evaluated on day 11.5 for increased expression of inducible conceptal cytochrome P450 (P450). The three agents each elicited concentration-dependent increases in 7,8-benzoflavone (ANF)-inhibitable ethoxyresorufin O-deethylase (EROD) activities and increased P4501A1 mRNA as detected by primer-specific reverse transcriptase-polymerase chain reaction (RT-PCR) in cell-free preparations of the treated, cultured conceptuses. At effective inducing concentrations, dysmorphogenic or other embryotoxic effects were not detectable. At 20 microM concentrations, the three agents exhibited roughly equal induction that was approximately equivalent in magnitude (6- to 13-fold) to that achieved previously with exposures to MC in utero. Additions to the culture medium of 2.5 to 10 microM concentrations of dexamethasone (DEX) did not alter significantly the magnitude of MC-elicited induction in vitro. Repeated full-length sequencing of an RT-PCR-amplified cDNA revealed a coding region sequence identical to that reported for the P4501A1 sequence from adult rat liver. The results provide a basis for investigations, in the absence of maternal influences, of the regulation of mammalian conceptal P4501A1 in intact tissues during organogenesis, a gestational period critical in terms of the dysmorphogenic and other embryotoxic effects of foreign organic chemicals. The results are also pertinent to studies of embryotoxicity, particularly to the transplacental carcinogenicity, mutagenicity and dysmorphogenicity of P4501A1 substrates.

Animals↗
PubMed1994

The nature of conditioned anti-analgesia: spinal cord opiate and anti-opiate neurochemistry.

The central nervous system contains circuitry that inhibits pain sensitivity (analgesia), as well as circuitry that opposes pain inhibition (anti-analgesia). Activation of analgesia systems and anti-analgesia systems can each be brought under environmental control using classical conditioning procedures. Analgesia can be produced by cues present before and during aversive events such as electric shock, while active inhibition of analgesia comes to be produced by cues never present immediately before or during shock and therefore signal safety. We have recently reported that these analgesia and anti-analgesia systems interact at the level of the spinal cord. A series of 3 experiments were performed to examine how such interactions occur. First, potential opioid mediation of conditioned analgesia was investigated using systemic and intrathecal (i.t.) delivery of opiate antagonists. Conditioned analgesia was found to be mediated by activation of spinal mu and delta opiate receptors. Second, analgesia produced by each of these receptor subtypes was challenged by environmental signals for safety. Analgesias produced by mu and delta opiate agonists were each abolished by safety signals. Third, antagonists/antisera directed against several putative anti-opiate neurotransmitters were tested i.t. to identify which mediate conditioned anti-analgesia at the level of the spinal cord. A cholecystokinin antagonist abolished conditioned anti-analgesia. In contrast, neuropeptide FF antiserum and a kappa opiate antagonist were without effect.

Analgesia↗
PubMed1994

Role of transesophageal echocardiography in pre- and post-percutaneous balloon mitral valvuloplasty.

Transesophageal echocardiogram (TEE) was performed in 33 consecutive patients with both rheumatic mitral stenosis and chronic atrial fibrillation to evaluate the usefulness of this technique for the detection of left atrial thrombi, mitral regurgitation before percutaneous balloon mitral valvuloplasty and iatrogenic atrial septal defect after the procedure. TEE correctly identified thrombi in 10 (30%) patients and significant mitral regurgitation in 5 patients who underwent surgical intervention. The remaining 18 patients underwent percutaneous balloon mitral valvuloplasty without evidence of systemic embolic event and obtained adequate outcome. Transesophageal color doppler echocardiography demonstrated left-to-right shunting flow through atrial septum in 5 of 7(71%) patients 3 days after the procedure and repeated TEE in 2 of these 5 patients showed no shunting after 6 months. In conclusion, TEE plays a definite role in the selection of patients for balloon mitral valvuloplasty and assessment of iatrogenic atrial septal defect.

Adult↗
PubMed1994

Functional cytochrome P4503A isoforms in human embryonic tissues: expression during organogenesis.

Expression of functional cytochrome P450 (CYP) isoforms in human embryonic tissues was explored during organogenesis (days 50-60 of gestation) with substrate probes, inhibitor probes, and immunoprobes and by reverse transcription-polymerase chain reaction (PCR), cloning, and sequencing. Evidence was obtained for the presence of relatively high levels of one or more functional CYP3A isoforms in embryonic livers. This was manifested as relatively extensive hydroxylation of (R)-warfarin at carbon 10 and as triacetyloleandomycin-inhibited O-debenzylation of benzyloxyresorufin when human embryonic hepatic microsomal fractions were used as enzyme sources. Immunoblots with anti-CYP3A4 antibody exhibited a strong signal in embryonic hepatic tissues but, in contrast, indicated very low or negligible CYP3A levels in human embryonic lung, kidney, heart, adrenal, and brain tissues. To explore expression of individual members of the CYP3A subfamily in human embryonic hepatic tissues at this early gestational stage, CYP3A cDNA was generated by reverse transcription, amplified by PCR, cloned, and sequenced. Oligonucleotide primers used for PCR were designed to flank target sequences unique to CYP3A but also common to all human CYP3A subfamily members for which GenBank nucleotide sequence information was available (CYP3A3, CYP3A4, CYP3A5, CYP3A5P, and CYP3A7). Sequencing data indicated that plasmids in 58 of 59 recombinant positive colonies contained an insert with a sequence identical to that present in CYP3A7 cDNA and the plasmid of only one colony contained an insert with a sequence identical to that present in CYP3A5 cDNA. No evidence was found for expression of CYP3A3 or CYP3A4. Thus, during organogenesis, human embryonic hepatic tissues express primarily CYP3A7 and are capable of significant CYP3A7-catalyzed xenobiotic monooxygenation during this very early stage of gestation.

Base Sequence↗