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Biomedical subjects

H Sang

Publications and source records attributed to H Sang.

35 records · Page 2Linked to original sources
PubMed1998

Transposition of the Drosophila element mariner into the chicken germ line.

The ability of the Drosophila transposable element mariner to transpose in the chicken was tested using a plasmid carrying an active mariner element injected into chick zygotes. Surviving embryos and chicks were analyzed for presence of mariner. Analysis of embryos that survived for at least 12 days of development indicated that mariner had transposed at high frequency into the chicken genome. Germline transmission of mariner from one of three surviving birds confirmed transposition. Analysis of the first-generation (G1) chicks showed that they each contained between one and three copies of mariner. Six different transposition events were represented in the G1 birds, and the transposition was catalyzed by expression of the mariner element's transposase gene. Transmission from G1 to G2 occurred at a 1:1 ratio. Mariner therefore has potential for development as a vector for transgenesis in avian species.

Animals↗
PubMed1997

The structure of free radical metabolites detected by EPR spin trapping and mass spectroscopy from halocarbons in rat liver microsomes.

Electron impact (EI) tandem mass spectrometry (MS/MS) combined with EPR spin trapping was used to detect and identify the free radical metabolites of various halocarbons in rat liver microsomal dispersions. EPR spectra of the spin adducts of radical metabolites derived from fluorine-containing halocarbons display fluorine hyperfine splitting, which can be used as proof for the identification of this kind of halocarbon-derived free radical spin adduct. For halocarbons without fluorine atoms, MS/MS was found to be a very useful and simple method for the detection and identification of the structures of halocarbon-derived spin adducts from radical metabolites. The molecular ions from spin adducts of these halocarbon-derived free radical intermediates were observed for the first time by scanning the precursor ion spectrum of m/z 57. These assignments were further confirmed by the use of perdeuterated tert-butyl PBN which provides the precursor ion spectrum of m/z 66.

Animals↗
PubMed1996

[Effect of bone xenograft transplantation on total T lymphocyte and its subset counts in mouse blood and spleen].

Fresh calf cancellous bone xenograft (FX), antigen free cancellous bone carrier (BC) and reconstituted bone xenograft (RBX) were inplanted in the thigh muscle pouches of Balb/c mice. Histological examinations were done at 7, 14 and 28 days postoperation, and indirect immunofluorescence was used to determine the positive counts of Thy1, L3T4, Lyt2, and Tac T lymphocyte of the blood and spleen at the same time, with the normal mouse lymphocytes as control. There was no significant difference between the BC implanted group and the normal (control) group, while the FX group had a significant increase rates of Thy1, L3T4 and Lyt2, especially of Tac lymphocytes. The RBX implanted group had no increase of Tac but increase of Thy1 and Lyt2. Th-Ts ratio decreased, and it was probably caused by bovine bone morphogenetic protein (bBMP) in the RBX. Histologically, intense immune rejection was noted in FX implanted group but not in the other two groups. Heterotopic ossification was noted in the RBX implanted group. FX increased intense immunologic rejection in the host, bat RBX did not, that might be due to the decrease of Th/Ts caused by bBMP. Tac lymphocyte count may indicate the immunologic rejection of bone xenograft transplantation.

Animals↗
PubMed1996

[A comparative study of ethylene oxide and ionizing radiation for sterilizing bone grafts].

To find a good way for sterilization and disinfection of bone grafts, we compared the sterilization capacity of gaseous ethylene oxide (EO) and cobalt-60 gamma radiation. The bone chips were contaminated with 10(7) bacteria per milliliter of Staphylococcus aureus ATCC 25923, Bacillus subtilis globigii 8017 and Bacillus cereus 4001, then sterilized with various doses of gaseous EO or cobalt- 60 gamma radiation. The sterilization effect of EO was more stronger and faster than that of 60Co gamma radiation. The application of moderate doses of EO for sterilizing particulate bone grafts was recommended.

Animals↗
PubMed1994

Transgenic chickens--methods and potential applications.

The development of techniques for the genetic manipulation of poultry has lagged behind the technology available in mammalian systems, although several different approaches are being taken to overcome the problems associated with the manipulation of avian embryos. Several methods being developed for generating transgenic chickens are giving promising results, and the production of transgenic chickens by DNA microinjection has recently been demonstrated. Exploitation of this technology, in both basic and applied research, is now a possibility, and many applications of transgenic technology to poultry breeding and novel uses of transgenic chickens have been suggested.

Animals↗
PubMed1994

Transgenic birds by DNA microinjection.

We have developed a method for production of transgenic chickens by DNA microinjection of chick zygotes followed by ex vivo embryo culture. The fate of plasmid DNA microinjected into the germinal disc of zygotes was analyzed in embryos which survived for at least 12 days in culture. Approximately half of the embryos contained plasmid DNA, 6% at a level equivalent to one copy per cell in all tissues analyzed. Seven chicks, 5.5% of the total number of injected ova, survived to sexual maturity. One of these, a cockerel, transmitted the exogenous DNA to 3.4% of his offspring. These G1 birds have reached sexual maturity and have been bred to produce transgenic offspring, demonstrating that stable transmission of foreign DNA can be obtained by our method.

Animals↗
PubMed1991

Recombinant human nerve growth factor infusions prevent cholinergic neuronal degeneration in the adult primate brain.

Atrophy of cholinergic neurons is a prominent component of Alzheimer's disease, and may explain in part the profound memory loss that is characteristic of patients with this disorder. Previous studies in animal models have shown that infusions of nerve growth factor into the adult brain can prevent both age-related and lesion-induced cholinergic neuronal atrophy. Recently, recombinant human nerve growth factor was found biologically active in nonprimate animal models. In the present experiment, recombinant human nerve growth factor infusions into the brains of adult primates prevented lesion-induced cholinergic neuronal degeneration and promoted cholinergic neurite sprouting. These findings provide additional support for potential therapeutic trials of human nerve growth factor in patients with Alzheimer's disease.

Alzheimer Disease↗
PubMed1990

Preliminary observations on the phenotypes of lymphoid cells in mycosis fungoides using anti-human-thymocyte monoclonal antibodies.

The phenotypes of lymphoid cells from twelve patients with mycosis fungoides (including 5 patients in the tumor stage and 7 in the pretumor stage) were determined immunohistochemically using anti-thymocyte monoclonal antibodies (HIT1, HIT2, and Leu 6). The results showed significant differences between the numbers of HIT1 and HIT2 positive cells in tumor and pretumor stage lesions, indicating that these two monoclonal antibodies may be of help in the staging of mycosis fungoides and in making a prognosis. Also, we found that some Leu 6 (+) cells in tumor stage lesions were round or oval in shape without dendritic processes, suggesting that they may be immature lymphocytes.

ADP-ribosyl Cyclase↗
PubMed1989

Episomal replication of cloned DNA injected into the fertilised ovum of the hen, Gallus domesticus.

We describe preliminary experiments to analyse the fate of cloned DNA microinjected into the cytoplasm of the chick fertilised ovum. The reporter gene construct pRSVcat was injected into the germinal disc before the first cleavage division, and the chick embryos were cultured for up to 7 days using the method of Perry (Nature 331:70-72, 1988). Linear plasmid molecules ligated rapidly after injection to form high-molecular-weight DNA molecules consisting mainly of random concatemers of the injected plasmid. Recombination involving circular molecules resulted in head-to-tail multimers of the plasmid. Some of the DNA was lost after injection, but the remainder was replicated approximately 20-fold during the first 24 h of development. Between days 1 and 7 in culture, the DNA was gradually lost and diluted out as the embryos developed. By day 7 in culture plasmid DNA was detectable in only 30% of the cultures analysed. No evidence for chromosomal integration of the exogenous DNA was obtained, suggesting that the plasmid DNA persisted episomally. Expression of the reporter gene construct pRSVcat was detected in day 2 and day 7 embryos.

Animals↗
PubMed1987

Effect of the acute administration of high dose pentobarbital on human brain stem auditory and median nerve somatosensory evoked responses.

Brain stem auditory (BAERs) and median nerve somatosensory evoked responses (MnSSERs) were recorded from normal neural pathways during the induction of pentobarbital coma in six patients undergoing elective excision of complex arteriovenous malformations. Each patient received a 33-minute infusion of pentobarbital at a rate of 0.6 mg/kg (total dose, 19.8 mg/kg). This regimen resulted in burst suppression or isoelectricity of the electroencephalogram in all patients. Although statistically significant changes in latency and amplitude occurred, both BAERs and MnSSERs were readily recordable in all patients throughout the infusion. For the BAER, there were significant increases in the latencies of Waves III and V. However, these increases are sufficiently small that misinterpretation of these changes as an evolving neurological injury is unlikely, e.g., Wave V latency increased from 6.25 +/- 0.25 (SD) to 6.58 +/- 0.16 ms (P less than 0.006). For the MnSSER, changes of greater potential clinical relevance were observed. There were substantial increases in the latencies of the early components of the primary cortical response and in the central conduction time (e.g., CCT of 6.1 +/- 0.6 ms preinduction vs. 7.7 +/- 1.1 ms at t = 33 min, P less than 0.003), and the amplitude of the early cortical response (N20-P25) decreased by a mean of 45% (P less than 0.02). By contrast, subcortical components of the MnSSER (brachial plexus, upper cervical spine) were only minimally affected. We conclude that, in patients who are initially neurologically intact, BAERs and MnSSERs can be monitored effectively during pentobarbital coma and that the loss of these responses should not be ascribed to the effects of this drug alone. However, the interpretation of evoked response changes, particularly MnSSER changes, that occur during pentobarbital administration should take into account the dose-related changes in latency and amplitude that we have observed.

Adult↗
PubMed1981

Complete recovery from hemiplegia following excision of a giant basal ganglia arteriovenous malformation.

A young female harbored a large arteriovenous malformation (AVM) in the basal ganglia associated with marked arteriovenous shunting. The complete recovery of her neurological deficit subsequent to excision of the AVM illustrates the reversibility of such severe cerebral impairment. Large lesions in the basal ganglia often have been deemed inoperable. However, modern advances in microsurgical techniques have provided the necessary illumination, magnification, and instrumentation that was needed for the exposure and gentle resection of the lesion in our patient.

Adult↗
PubMed1975

Surgical treatment of intracranial vascular malformations.

Arteriovenous malformations often pursue a progressive course, increasing in morbidity and mortality. Whenever possible they should be excised totally. The operating microscope, bipolar coagulation and high quality angiography have extended the generally accepted indications for surgical operation. Intraoperative adjuncts of contrast angiography and cardiac green have been helpful in accurately defining deep or complex lesions.

Adolescent↗
PubMedDate not supplied

Genetic and physical mapping of the chicken IGF1 gene to chromosome 1 and conservation of synteny with other vertebrate genomes.

The chicken insulin-like growth factor 1 gene has been assigned to the short arm of chromosome 1 near the centromere by fluorescence in situ hybridization and genetic linkage analysis. Comparison of physical and genetic linkage maps locates the centromere between the IGF1 and GAPD loci. Comparison of the genetic maps of chicken and other vertebrates reveals a highly conserved syntenic group, including the GAPD-IGF1 loci.

Animals↗