Fragile X syndrome: diagnosis using highly polymorphic microsatellite markers

We describe two highly polymorphic microsatellite AC repeat sequences, VK23AC and VK14AC, which are closely linked to the fragile X at Xq27.3. Both VK23AC (DXS297) and VK14AC (DXS292) are proximal to the fragile site. Two-point linkage analysis in 31 fragile X families gave (a) a recombination frequency of 1% (range 0.00%-4%) with a maximum lod score of 32.04 for DXS297 and (b) a recombination frequency of 7% (range of 3%-15%) with a maximum lod score of 12.87 for DXS292. Both of these polymorphisms are applicable to diagnosis by linkage in families with fragile X syndrome. A multipoint linkage map of genetic markers at Xq27.3 was constructed from genotyping these polymorphisms in the CEPH pedigrees. The DXS292 marker is in the DXS98-DXS297 interval and in 3 cM proximal to DXS297.

[The relation between ventricular late potential and ventricular arrhythmia in different stages of acute myocardial infarction]

50 cases of acute myocardial infarction (AMI) were examined for ventricular late potential (VLP) six times in total within 4 weeks. At the same time the patients clinical condition was observed. It is found that: (1) In our group the occurrence of VLP in AMI was 28% and VLP was unstable in both acute stage and recovery stage. (2) During acute stage, the difference of positive VLP rate is significant between the ventricular fibrillation group and normal rhythm group (P less than 0.05), but there is no significant difference between the ventricular ectopia group and normal rhythm group. During recovery stage, the difference of positive VLP rate is very significant between the ventricular ectopia and normal rhythm group (P = 0.001). As there was only 1 case of ventricular fibrillation occurring in the recovery stage, no comparison could be made. (3) There is no correlation between VLP and clinical conditions, such as age sex, location of the infarction, existence of old infarction and LVEF. However, the difference of the peak serum CPK level is significant between VLP positive and negative group (P less than 0.05).

[The absorption of Fe, Zn, Cu in siwu, sijunzi, and Liuwei dihuang decoction by small intestine in rats]

In this study the absorption of Fe, Zn and Cu in decoctions of siwu decoction, sijunzi decoction and liuwei dihuang decoction by the small intestine in anesthetized rats was observed. The experimental results showed that the absorption of Cu and Fe from siwu decoction was much higher than that from other decoctions which might be related to the hematopoietic function of Cu and Fe rich in the decoction.

[Effect of rhizoma Zingiberis on anoxic or cooled mice]

The anti-anoxic experiments have indicated that the petroleum ether extract of Rhizoma Zingiberis can prolong the survival time in mice poisoned by KCN or under the condition of normobaric hypoxia, as well as decapitation-induced gasping duration in mice, but can not prolong the survival time in mice poisoned by NaNO4. The anti-anoxic action might be related to the reduction rate of O2 consumption of the body. The aqueous extract of Rhizoma Zingiberis does not possess the above-mentioned anti-anoxic action. Both extracts do not affect the survival time in cooled mice.

[XbaI polymorphism in intron 22 of factor VIII and gene potential for prenatal diagnosis of hemophilia A]

Polymorphism of an XbaI restriction endonuclease site in intron 22 of the factor VIII gene was studied. 79 heredity-unrelated X chromosomes from 83 Chinese were analyzed. The frequency of the polymorphic site was 0.56, providing polymorphism information content (PIC) of 0.49. Fourteen out of 17 families with hemophilia A could be diagnosed by the Xba 1/22i restricted fragment length polymorphism (RFLPs). Therefore, as a genetic marker within the factor VIII gene, Xba I/22i RFLPs should be useful for prenatal diagnosis of hemophilia A and for detection of its carriers.

Study on BcII/St14 RFLPs in Chinese for DNA diagnosis for hemophilia A

The BcII polymorphism within DXS52 (St14) was reported. It was composed of 4 allelic fragments, 4.0 kb, 3.3 kb, 3.0 kb and 2.3 kb. The frequency of these fragment were 0.09, 0.12, 0.44 and 0.35 respectively in the Chinese. The polymorphism provided the PIC of 0.66. DNA analysis of families with hemophilia A showed that the confidence of the RFLPs was the same as the TaqI/St14 RFLPs and for carrier detection the former is much better than that of the TaqI/St14 RFLPs.

Glycinamide ribonucleotide synthetase from Escherichia coli: cloning, overproduction, sequencing, isolation, and characterization

The purD gene of Escherichia coli encoding the enzyme glycinamide ribonucleotide (GAR) synthetase, which catalyzes the conversion of phosphoribosylamine (PRA), glycine, and MgATP to glycinamide ribonucleotide, MgADP, and Pi, has been cloned and sequenced. The protein, as deduced by the structural gene sequence, contains 430 amino acids and has a calculated Mr of 45,945. Construction of an overproducing strain behind a lambda pL promoter allowed a 4-fold purification of the protein to homogeneity. N-Terminal sequence analysis and comparison of the sequence with those of other GAR synthetases confirm the amino acid sequence deduced from the gene sequence. Initial velocity studies and product and dead-end inhibition studies are most consistent with a sequential ordered mechanism of substrate binding and product release in which PRA binds first followed by MgATP and then glycine; Pi leaves first, followed by loss of MgADP and finally GAR. Incubation of [18O]glycine, ATP, and PRA results in quantitative transfer of the 18O to Pi. GAR synthetase is very specific for its substrate glycine.

Effects of nimodipine on medial septal area cells after section of the fimbria-fornix

In rats, sectioning the fimbria-fornix leads to a decrease in cells reactive for acetylcholinesterase and choline acetyltransferase, as well as other types of cells, in the medial septal area that project to the hippocampus. In this study cells in the medial septal area were stained for acetylcholinesterase reaction product or by a Nissl method two weeks after unilateral section of the fimbria-fornix. Counts were made of cells on each side of the midline by independent observers. The counts of the cells on the two sides of the brain were compared in rats that had been given nimodipine (70 μg/kg) just after the lesion and for 7 additional days and in rats that had been given only the vehicle for an equivalent amount of time. The number of cells reactive for acetylcholinesterase was reduced in the medial septal area on the side of the brain in which the forebrain fornix was sectioned, but this occurred to a significantly less extent in the nimodipine-treated rats. No differences were noted in the number of cells on the two sides of the medial septal area when counted in Nissl-stained sections.

[Gene diagnosis of hemophilia A]

Hemophilia A is the most common inherited bleeding disorder in man. The disease is caused by a deficiency in the gene for factor VIII. A genetic marker in the form of RFLP within or tightly linked to the factor VIII gene may serve as a tag for the hemophilia gene, thus allowing both accurate carrier detection and earlier prenatal diagnosis. Five RFLP (BclI/FVIII-e18, XbaI/FVIII-i22, BclI/St14, TaqI/St14 and BglII/DX13), which are related to hemophilia gene, were studied. The frequencies of allele of TaqI/St14 and BglII/DX13 in Chinese are obviously different from those in Caucasian. By the use of RFLP, 21 families with hemophilia A were analysed. The feasibility and strategy of gene diagnosis of hemophilia A by the use of RFLP are discussed.

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.

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.