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.

Haloperidol concentrations elevated in Chinese patients

After 6 weeks of fixed dose oral haloperidol treatment. Chinese schizophrenic patients (in the People's Republic of China) had 52% higher plasma haloperidol concentrations than U.S. non-Asian schizophrenic patients. Chinese and U.S. patients were matched for sex and body weight. The difference in plasma drug concentrations may explain why Asians are reported to require smaller dosages of neuroleptic drugs than non-Asians, and why they may be more sensitive to neuroleptic-induced side effects. When prescribing haloperidol to persons of Asian ancestry, physicians should consider that higher than expected plasma haloperidol concentrations and an increased sensitivity to haloperidol may occur.

The long-acting Ocusert-pilocarpine system in the management of glaucoma

The Ocusert-pilocarpine devides with seven days' therapeutic duration were compared with pilocarpine eye drops for efficacy and ocular tolerance in the management of glaucoma in 16 patients. Magnitude of pressure reduction with release rates of 20 mcg. and 40 mcg. of pilocarpine per hour were as effective in the treatment of glaucoma as 2 per cent and 4 per cent pilocarpine eye drops, respectively. Ocular tolerance and retention in the human eyes were good. There were no appreciable side effects other than the occasional sudden leakage phenomenon encountered. Further refinement of the Ocusert-pilocarpine device to reduce the incidence of leakage would not only ensure precision in the rate of drug release, but would also expand its clinical application.