A study of sex identification of trace, dried bloodstains using a Y-chromosome-specific deoxyribonucleic acid (DNA) probe

A new method is discussed which examines trace, dried bloodstains by gel in situ hybridization using a Y-chromosome-specific deoxyribonucleic acid (DNA) probe to determine the sex of the bloodstain for forensic medicine application. The complete DNA is transferred directly by electrophoresis onto the gel intact, bypassing the possibilities of impurities contaminating the sample and of DNA degradation. The method has proven accurate for small (2.5-mm-diameter) samples aged up to eight years and is quick, simple, and easily read.

Establishment, characteristics, and utilization of a new in vivo-in vitro system

Radiotherapy and chemotherapy are two important methods for malignant tumor treatment. To research radiobiological response in therapy, we have established a better experimental method in contrast to the traditional ones such as TCD50, regrowth delay, cell survival curve, etc, all with their limitations. A new mouse tumor in vivo-in vitro system LA795 Vv-Vt has been developed for studies on radiobiology. Such a system could be used to study the in vivo response of a solid tumor by the in vitro cloning assay. For the purpose of increasing the PE in vitro, LA795 Vv-Vt tumor line was purified through culturing the cells as a clonogenic spheroid. The spheroids were then injected into the flank of mouse subcutaneously for tumor growth. The in vivo-in vitro system LA795 Vv-Vt is an excellent model dissecting and analyzing the various factors which affect tumor development and determine the response of tumor to specific agent and regimens.

The use of Chinese herb medicine in experimental radiotherapy

Extracts from a group of destagnative herbs, 764-1, and the effective chemical, 764-3, were tested by an in vitro experiment using a HeLa-S3 cell line. Under aerobic conditions, the shoulder of the cell survival curve diminished or disappeared according to the different doses of 764-1 used, but no change in slope was observed. In nitrogen, when the dose of 764-1 increased to 20 mg/ml (ID20), besides the disappearance of the shoulder, the slope of the curve also showed changes at lower doses (4-8 Gy); up to 10-25 Gy the curve became more flattened. 764-3 showed almost a similar effect by mainly affecting the shoulder of the survival curve. At low drug doses a SER as high as 1.87 might be obtained under hypoxic condition. At the same time 764-1 was used in testing the effect on radiation lung damage. It was found that 764-1 could markedly inhibit the change of alveolar surfactant at 1 and 3 weeks after radiation. A wide field of investigation is thus spread out in front of us on radiosensitization and protection. Further studies on 764-3 are carried out.

Restriction primer extension method of labeling oligonucleotide probes and its application to the detection of Hb E genes

A new method for labeling oligonucleotides was developed to obtain high specific activity of radioactive probes. In an oligonucleotide molecule, two sequences were designed. One sequence, the 5', contains 19 nucleotides and serves as a template for probe synthesis. The second sequence, 3', contains a consensus sequence which forms a Pst I site after forming a complementary strand with the primer. In the presence of E. coli DNA polymerase I (Klenow fragment), alpha-32P dNTP and other dNTPs, a radioactive labeled oligonucleotide was synthesized by the primer extension method. After Pst I digestion, the probe was different from its template in length by 4 bp and could be separated from each other on urea-polyacrylamide gel electrophoresis (PAGE). A radioactive oligonucleotide probe with extremely high specific activity up to 10(10) dpm/micrograms could be obtained by the use of this method. The oligonucleotide probes have been used for the detection of the Hb E mutation in this report.

[Establishment of a human colonic carcinoma xenograft in nude mice and its chief biological characteristics]

A human colonic cancer specimen cut into 1-2 mm3 pieces under aseptic condition was heterotransplanted hypodermically by trocar to the inguinal region of BALB/cATcL nude mice bred in our laboratory. 53 days later, a 10 X 9 X 11 mm3 tumor was obtained. The take rate was 100% (48/48). The take rate of liquid nitrogen frozen and recovered tissue pieces was also 100% (13/13). Grossly, the tumor was rich in blood supply and well encapsulated. Within the tumor, the tissue was cream-colored. G-banded chromosome analysis revealed a human chromosome pattern with the mode 70-90. Pathologic diagnosis was signet-ring cell cancer, which was identical to the surgical specimen. No change was found after maintaining 13 passages in nude mice. It was named the human colonic carcinoma xenograft XHCn/w. It provides an ideal tumor model for in vivo or in vitro experiments.

[In vivo experiments, in vitro assays in experimental oncology: establishment of LA 795 Vv-Vt]

In vivo experiment, in vitro assays (in vivo-in vitro system) is a kind of experimental technique which is different from both in vitro cell line and tumor line. The new model can be grown and studied either as an animal tumor or a cell culture. The specimen could be assayed for cell survival in vitro. This model can be used to study the response of malignant cells to the treatment in a precision and depth that is impossible in tumors grown in vivo. LA 795 Vv-Vt is the first in vivo-in vitro system developed in China. It was established with lung adenocarcinoma of T-739 mouse. The tumor cells could grow freely both in vivo and in vitro with a plating efficiency of 20%. Characteristics of LA 795 Vv-Vt tumor and cell in culture were described and compared. In order to estimate the radiation response of different doses, cell survival curves of tumors irradiated under oxic and hypoxic conditions were drawn and compared. The oxygen enhance ratio was 2.98. The experiments indicate that in vivo-in vitro system has a good dependent relation in dose and effect and is worth extensive application.