Biomedical subjects
Publications and source records attributed to H Dai.
The high resolution G band of human chromosomes at 1200 band stage was analyzed under microscope and every band was identified based on the 850 band stage chromosome diagram of ISCN (1985). A set of photographs of haploid set chromosomes at 1200 band stage was presented on which every dark band was marked.
A sampling survey of medical exposure frequency covered 15,000 hospitals in 24 provinces, while a sampling measurement of patient doses covered 2,000 hospitals in 14 provinces. From these surveys and measurements, we compiled survey data of 11 million cases. The data were analyzed by computer, and the frequencies, averages of skin and organic dose per examination, and population doses per capita (He, LSD, GSD, SSD) were found. The possible risks of medical exposure in China are also estimated in this paper.
A polyglycosides of Tripterygium wilfodii hook F (TWH) preparation with a code name of T2 is used in the present double-blind, controlled, cross-over study on the treatment of 70 cases of rheumatoid arthritis (RA). An impressive curative effect of T2 is confirmed much more convincingly by the present study than that by the previously reported clinical open trials. The adverse reactions and the probable pharmacological mechanism of T2 are also discussed.
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Filamentous phage Cf16 undergoes a unique neolysogenic infectious cycle in Xanthomonas campestris pv. citri and generates stable lysogens. In contrast, we have isolated a distinctive unstable lysogen, designated LW. This new lysogen segregated spontaneously into three nonparental types, each with a unique combination of colony morphology, phage-producing capacity, and phage genome content. In a given population of LW lysogens the segregation frequency of these types varied randomly with drastic fluctuations from experiment to experiment. Heat and UV treatment failed to increase the segregation frequency with a magnitude matching the sporadic intrinsic fluctuations. The characteristics of an LW lysogen were transmitted through the phage it released. Designated as Cf16-v1, this phage, which produced clear instead of turbid plaques as its progenitor Cf16, was exceedingly unstable in the host cell. Only 4% of the infected cells, rather than 95% as in the case of Cf16, retained the phage genome and completed the neolysogenization process. The prophage integration site on the host chromosome, however, appeared to be the same for both phages.
Following a protracted carrier state in the infected cell, filamentous bacteriophage Cf16-v1 neolysogenizes Xanthomonas campestris pv. citri by inserting the phage genome into the host chromosome. The integration region in the phage and the host chromosome, respectively, and the two junctions in the lysogen chromosome were isolated and their nucleotide sequence was determined. The phage and host attachment sites shared an identical 15-bp "core," 5'-TATACATTATGCGAA-3'. Located on either side of each core were two unique arm sequences. Each of the two phage-host junctions contained an intact core flanked by a hybrid combination of phage and host arm sequences. A 10-bp symmetrical sequence arranged as inverted repeats with 1-bp spacing straddled the core sequence. A 10-bp repeated sequence, 5'-GCGCTATGGC-3', was found distal to the core in opposite orientation at the phage attachment site, while an abbreviated form of this sequence was present in the host attachment site. These sequence characteristics indicate that neolysogenic insertion of Cf16-v1 was accomplished by a site-specific recombination mechanism similar to lambda integration. However, in contrast to lambda, the phage and the host attachment sites in the Cf16-v1 system contained a high G + C nucleotide bias (except for the core sequence itself).
Stability of carrier state in filamentous phage-infected Xanthomonas campestris pv citri varied drastically even for closely related phage types. The spontaneous curing frequency for cells infected with Cf16-12, Cf16, Cf16-v1 and Cf was 1, 5, 96 and 100%, respectively. The size of the phage replicative-form (RF) pool which built up rapidly at the onset of Cf16 infection was critical to the maintenance of the carrier state and the eventual integration of the prophage. A correlation in stability between phage carrier state in infected cells and lysogeny was found for these phages. The past history of a phage infection altered the response of the cured host to reinfection. In those cured cells which remained susceptible, the stability of the reinfecting phage genome was not altered appreciably, while a distinctive new plaque morphology appeared in greater than 50% of these cells. These alterations were not dependent on the prophage integration prior to curing, and no phage DNA was detected in cured cells by blot hybridisation. Notwithstanding these changes, the sites of phage integration in cured cells remained the same as the original infection on both the phage RF and the host chromosome.
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DNA enriched for supercoiled plasmids prepared from the 3 micron plasmid-enriched, [psi+], [2 micron degrees] strain 6-1G-P188 and from the [2 micron+] [psi+] strain LL20 can be used to transform a psi- recipient strain to psi+. Fractionation of the former preparation by electrophoresis showed that the 3 micron plasmid band contained the transforming activity.
Plasmid RP4 were transferred from Escherichia coli into Pseudomonas solanacerum, Xanthomonas campestris pv. oryzae, X. campestris pv. campestris, and X. campestris pv. citri at the frequencies of 1.8 X 10(-6), 2.8 X 10(-6), 1.4 X 10(-2) and 2.0 X 10(-3), respectively. The frequencies of transfer depended on bacterial species and conjugation conditions. Treatment of bromide at the concentration of 2 micrograms/ml and acridine orange at 100 micrograms/ml for 32 hrs the plasmid RP4 could be cured from the transconjugant of P. solanacerum at the frequencies of 75% and 95%, respectively. When transconjugant of P. solanacearum was inoculated into tomato plants, the decrease in virulence was observed, furthermore, no plasmids were detected both in the wild-type strain and the cured transconjugant. It thus appears that the virulence may not be related to plasmids.
BACKGROUND: In short-term studies, diet and exercise both improve insulin sensitivity. OBJECTIVE: To determine the effects of a 48-week supervised diet and exercise program on weight and insulin sensitivity after initial weight loss and weight maintenance, and then subsequent weight regain over 96 weeks. METHODS: Forty-five obese women were randomly assigned to 1 of 3 treatment groups: (1) diet alone, (2) diet and aerobic training, and (3) diet and strength training. All subjects received the same 48-week group behavior modification program and diet (approximately 3879 kJ/d [approximately 925 kcal/d] for the first 16 weeks; approximately 6276 kJ/d [approximately 1500 kca/d] thereafter). Exercising subjects were provided 3 supervised exercise sessions per week for the first 28 weeks and 2 sessions weekly until week 48. During weeks 48 to 96, subjects were unsupervised. Oral glucose tolerance tests were performed at baseline and weeks 16, 24, 44, and 96. RESULTS: Subjects across the 3 conditions achieved a mean weight loss of 13.8 kg by week 16, which was associated with decreased insulin levels (61.8% of baseline) There were no significant differences among groups in changes in body mass index, which is a measure of weight in kilograms divided by the square of the height in meters, weight, glucose tolerance, or insulin levels at weeks 16, 24, and 44. No additional beneficial effect of aerobic or strength exercise on insulin resistance, as reflected by serum insulin levels before and after a glucose load, was demonstrated. The 22 subjects who were studied at week 96 maintained a loss of approximately 10% of initial weight. Insulin levels, however, had returned to pretreatment levels. CONCLUSIONS: This study confirms the beneficial effect of weight reduction on hyperinsulinemia in obese individuals. Participation in supervised exercise did not result in additional improvement in weight loss or insulin sensitivity. We also observed a marked increase in insulin levels with only partial weight regain. Determining the amount of sustained weight loss necessary for continued improvement in insulin sensitivity will require further study.
The US military has been an effective proponent of digital imaging and teleradiology for the past 15 years. A digital imaging network that can eliminate the use of X-ray film can make the requirements simpler for military medicine. X-ray film requires the storage of new, unexposed films that have a fixed shelf life, and the storage and use of chemicals and water for processing. In some deployed situations, the chemical discharge has to be collected and shipped out of the deployed area. The technology of electronic imaging is therefore intrinsically important to military medicine. In December of 1995, the US government started to deploy 20000 US troops to Bosnia-Herzegovina as part of NATO's peace keeping operation (IFOR). A full complement of medical support facilities was to be established in the Bosnia region and Hungary where the deployment was staged. Primetime III was a project to deploy telemedicine and teleradiology capabilities linking these medical treatment facilities (MTF). The deployment of telemedicine was not the responsibility of our engineering team. This paper deals with the deployable teleradiology (DEPRAD) system that was installed by the ISIS Center at a number of facilities for filmless radiology and teleradiology services.
A door-to-door two-phase study was used to investigate the prevalence of senile dementia in an urban community of Beijing. In the study population, 5,003 individuals aged 60 years and older (>/=65 years, n = 3,728) were screened at home with the Chinese version of the MMSE. Persons who screened positive for dementia, using different cutoff scores based on degree of literacy, were further evaluated using the criteria of DSM-III-R and ICD-10. Among subjects who screened positive in phase I, 134 were diagnosed as having dementia in phase II. The prevalence ratios of dementia were 2.68% in the population aged 60 years and older, and 3.49% in the population aged 65 years and older. The prevalence rates among those aged 65 years and older were 1.85% for Alzheimer's disease, 1.37% for vascular dementia and 0.27% for other dementia (including mixed dementia). The prevalence of all dementia and AD increased steeply with advancing age and was consistently higher in women, but it was not obviously higher for VaD in women. Alzheimer's disease was the commonest type of dementia. Our prevalence figures for dementia and AD are similar to those previously reported for China.