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Biomedical subjects

G Hong

Publications and source records attributed to G Hong.

7 recordsLinked to original sources
PubMed1992

In vitro replication of adeno-associated virus DNA.

An in vitro assay for adeno-associated virus (AAV) DNA replication has been developed. The substrate is a plasmid containing the duplex form of AAV DNA in pBR322. The AAV insert is excised or rescued from the plasmid by extracts of uninfected cells. Replication was assayed by production of full-length excised AAV DNA resistant to Dpn I digestion. The following results were obtained. (i) Only extracts of cells coinfected with AAV and adenovirus replicated the excised insert. (ii) Density label experiments showed semiconservative replication. (iii) Only the excised AAV insert was replicated; pBR322 sequences were not. (iv) Replication was dependent on the presence of the AAV terminal repeat. (v) If the terminal 55 bases were deleted from both ends of the AAV insert, no rescue took place: replication occurred and both AAV and pBR322 sequences were replicated. We conclude that the AAV terminal repeat is essential for DNA replication but that under some conditions an initiation mechanism that does not involve hairpin priming may be used.

Adenoviruses, Human↗
PubMed1992

Training in basic microsurgical techniques without experiments involving animals.

Until recently, anaesthetised rats have been the usual material employed for learning basic microvascular and microneurosurgical techniques. However, ethical considerations, the costs involved and legislation controlling experiments with animals allow training in microsurgery for extended periods of time at a few medical centres only. This paper reports on our experience of an alternative training programme largely conducted without using live animals. As the basic material we selected legs of slaughtered pigs. According to the developing skill of the trainee, basic microsurgical techniques can be practised on arteries and veins of various sizes in these legs. To verify positive results, the vessels are subsequently perfused with human blood under pressure. The model described is particularly suited to the acquiring of skills in microneurosurgery. Mono-, oligo- and polyfascicular nerves, structurally similar to the configurations found in human extremities, are found in pig legs. The ever-increasing importance of microsurgery in modern medicine requires more and more surgeons and orthopaedists to familiarize themselves with these techniques. The model we propose for teaching and training substantially facilitate such further professional training in an efficient way, and at the same time allows a substantial reduction in the number of experiments conducted on animals.

Animal Testing Alternatives↗
PubMed1992

Intragenomic movement and concerted evolution of satellite DNA in Peromyscus: evidence from in situ hybridization.

Four DNA probes isolated from Peromyscus leucopus were used to examine intra- and interspecific variation in the chromosomal location of satellite DNA in the genus Peromyscus. All four probes hybridized to the centromeric regions of all chromosomes in all species of Peromyscus examined but did not hybridize to the majority of heterochromatic regions in closely related non-Peromyscus species. One probe contains a nonsatellite repetitive sequence. The implications of these data to the evolution of genome organization are discussed.

Animals↗
PubMed1992

The reverse DNA sequencing using Bst DNA polymerase.

The reverse DNA sequencing (RDS) [1] is a rapid method used to check the DNA sequences by sequencing them from the opposite orientation. Because the RDS is basically a double stranded sequencing, the quality of the sequence patterns so obtained generally is not as good as those obtained by the single stranded sequencing, and extra bands and higher background are produced more frequently. This paper shows that the RDS could now generate as good sequence patterns as those obtained by sequencing on the single stranded DNA template if Bst DNA polymerase instead of the conventional enzymes, such as the Klenow enzyme, was used in the RDS. Bst DNA polymerase is heat stable (optimum reaction temperature 65 degrees C) and has recently been successfully used in the conventional DNA sequencing. The RDS has recently been further simplified to meet the need of large DNA sequencing projects such as the human genome project. The combination of the simplified RDS and the use of Bst polymerase should be expected to facilitate greatly the work on sequence confirmation and correction.

Base Sequence↗
PubMed1992

[A realistic practice model for learning microneural surgery without experiments on live animals].

The increasing importance of microneurosurgery in hand and plastic surgery makes it necessary for surgeons to familiarize themselves with these techniques. In most training programs, anesthetized rats have been used to learn basic microneurosurgical techniques. Ethical considerations, the costs involved, and the legislation concerning experiments with live animals permit extensive training in microneurosurgery in only a few medical centers. This paper relates our experience with an alternative training program not involving live animals. Instead, we chose the legs of slaughtered pigs. Mono-, oligo-, and poly-fascicular nerves, structurally similar to the configurations found in human extremities, can be found in pig legs. Neurolysis, primary nerve sutures, and nerve transplantations can be practiced.

Animal Testing Alternatives↗
PubMed1989

Effects of Chinese medicinal herbs on hemorheology in diabetics.

There was a statistically significant increase in whole blood viscosity, plasma viscosity, erythrocyte filterability index and hematocrit in diabetics with "Qi Yin deficiency and blood stasis" syndrome. After treatment with "Yi Qi Yang Yin Hou Xue" prescription there was a statistically significant improvement in hemorheological properties and a slight decrease in fasting blood glucose.

Adult↗