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Biomedical subjects

D Luo

Publications and source records attributed to D Luo.

At least 145 records · Page 8Linked to original sources
PubMed1991

Pigmentation mutants produced by transposon mutagenesis in Antirrhinum majus.

New pigmentation mutants were generated by transposon mutagenesis in Antirrhinum majus, in three previously described loci, nivea, delila and incolorata, and two new loci, daphne and olive. The wild-type olive gene is required for the production of dark-green leaves, and the daphne gene for the synthesis of flavones. Five out of the six mutants were both germinally and somatically unstable, indicating that they resulted from transposon insertions. Molecular analysis of the mutant at nivea (niv-600) showed that it was caused by insertion of a new transposon, Tam4. The sequence of Tam4 suggests that it is unable to transpose autonomously and that it is related to Tam1 and Tam2. All three of these transposons have identical inverted repeats, produce 3 bp target duplications, leave similar excision footprints and share at one end a 600-700 bp region containing many palindromic copies of a motif sequence, possibly required in cis for transposition. The somatic excision of Tam4 in niv-600 is at a very low rate compared to germinal excision but it can be activated by crossing to lines carrying derivative alleles of a Tam1 insertion at niv. Molecular analysis of four different pigmentation mutants has shown that insertions of Tam1, Tam2, Tam3 and Tam4 have been obtained, illustrating the potential of general transposon mutagenesis for trapping and isolating new transposons as well as for tagging genes.

Base Sequence↗
PubMed1991

[Prophylactic effect of refined amorphophallus konjac on MNNG-induced lung cancers in mice].

Three hundred and seventy LACA mice of seven weeks old were used in 2 batches for studying the prophylactic effect of Konjaku powder on MNNG-induced lung cancers. These mice (within each batch) were randomly allocated to four groups, namely positive control (MNNG), refined Amorphophallus Konjac (R.A.K.), complex (MNNG + R.A.K.), and blank control (C). In MNNG group, MNNG (250 micrograms) was injected intravenously once five days for seven times in each mouse, the total dosage of MNNG was 1.75 mg. In R.A.K. group, according to w/w, 8% R.A.K. was well mixed into 92% common diet for long-term term breeding. In complex group, MNNG was given as that in MNNG group and the mice were reared as those in R.A.K. group. The mice in MNNG group and in C group were all reared by common diet. The results of experiments showed different degrees of preventive effect of R.A.K. on MNNG-induced lung cancers in LACA mice. R.A.K. not only exerted effect on the number of induced cancer, causing a drop of the cancerous rate from 79.75% to 20.00% and the mean number of cancer in each animal, but also prolonged the survival time of animals. At the same time, the constituent ratio of the kinds of tumor denoted a decrease in malignancy (adenoma with malignant change), an absence of adenocarcinoma and relative increase in benign adenoma. The results of experiments also exhibited good duplication as well as absence of adverse reactions to Konjaku powder.

Animals↗
PubMed1991

[Emery-Dreifuss muscular dystrophy--reported a family with 5 cases].

Five cases of Emery-Dreifuss muscular dystrophy in four generations of a family was reported. It is a rare form X-linked recessive muscular dystrophy. The distinctive features of this disease are: Firstly, early contractures of elbows and achilles tendons and posterior cervical muscles are revealed. Secondly, muscle weakness is more proximal (scapulo-humeral) in the upper limbs and distal (anterior tibial and peroneal muscle) in the lower limbs. Thirdly, there is no calf pseudohypertrophy. Fourthly, myocardial involvement with cardiac conduction defects is frequent and important features. The CPK level is usually slightly raised. In our report, the EMG and muscle biopsies showed a mixed pattern of neurogenic and myogenic changes.

Adult↗
PubMed1991

[Studies on varietal resources of Chinese medicinal plants and their preservation].

The paper reviews the status of varietal resources of Chinese medicinal plants in China. The existing problems are analysed. Characteristics of these resources are dealt with. The results have shown that the study of varietal resources of Chinese medicinal plants must be strengthened for facilitating their production. Methods of varietal preservation of these plants are also discussed.

Conservation of Natural Resources↗
PubMed1991

Proteins isolated from regenerating sciatic nerves of rats form aggregates following posttranslational amino acid modification.

Soluble proteins of regenerating sciatic nerves of rats can be posttranslationally, covalently modified by a variety of radioactive amino acids. The present study shows that once modified by a mixture of 15 amino acids, many of those proteins form aggregates that are unable to pass through a 0.45-micron filter and pellet following 20,000g centrifugation (suggesting a size of greater than 2 x 10(6) Da). Aggregation of proteins also occurs following modification by Arg or Lys alone, but does not occur following protein modification in nonregenerating nerves or in brain. Aggregates are not disrupted by treatment with 100 mM beta mercaptoethanol or by exposure to 1.0 M NaCl, but aggregates are solubilized by treatment with urea and by boiling in 1.5% SDS. Amino acid analysis of proteins modified by a mixture of [3H]amino acids shows a similar proportion of posttranslationally incorporated Ser, Pro, Val, Ala, Leu, Phe, Lys, and Arg in the soluble and pelletable fractions. Two-dimensional PAGE profiles of soluble and pelletable modified proteins show that the modified proteins in both fractions are in similar pI and molecular weight ranges, except that the soluble modified proteins include a high-molecular-weight component that is absent in the pelleted modified proteins. Kinetic studies show that while half-maximal levels of protein modification occur within 30 seconds of incubation, the appearance of the pelletable modified protein fraction is delayed significantly. These results indicate that amino acid modification of soluble proteins in regenerating sciatic nerves of rats results in physical changes in those proteins so that they form high-molecular-weight aggregates.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1990

Amino acid modification of proteins in regenerating sciatic nerves of rats.

Recent experiments have shown that Arg, Lys, and Leu can be incorporated posttranslationally into proteins of regenerating sciatic nerves of rats. The present experiments investigate a mixture of 15 radioactive amino acids to determine if additional amino acids can be conjugated posttranslationally to proteins of regenerating nerves. Proteins of regenerating sciatic nerves of rats were able to incorporate Arg, Lys, Leu, Pro, Val, Ala, Phe, and Ser in relatively large amounts and Asp, Glu, Thr, Gly, Ile, His, and Tyr in relatively low or undetectable amounts, in the most advanced portion of the regenerating nerves. Two-dimensional SDS PAGE showed incorporation of the amino acid mixture into distinct radioactive peaks with molecular weights in the 80-90 kD, 53-66 kD, 22-46 kD, and 17 kD ranges with isoelectric points between 5.0 and 7.9. Most of the amino acids were incorporated into proteins in all of the molecular weight ranges. But Ser was incorporated in highest amounts in the 17 kD range, and Val was most abundant in the 22-46 kD range. In some cases results indicated that single proteins were modified by several amino acids. While we do not yet know which amino acids modify specific nerve proteins or the function of the modifications in nerve regeneration, these studies demonstrate the participation of some but not all amino acids in posttranslational modification reactions and the selective modification of specific groups of nerve proteins by these amino acids.

Amino Acids↗
PubMed1990

[Ultracytochemical observation on lysosome of hair cells in kanamycin ototoxic guinea pigs].

Using the ultracytochemical technique, we found the lysosome with high electronic density just beneath the cuticle plate in all normal hair cells; but in ototoxic group, the lysosome became multivesicular, expanded and displaced in hair cells. Occasionally the vesicles of the lysosome fused. In some of the hair cells, the cytoplasm dissolved, the membrane ruptured, the contents of the cells leaked out. In these cells the lysosome disappeared. We assume that the vesicle in the lysosome may be kanamycin and its metabolic products. The overloading and rupture of the lysosome can result in autolysis of the hair cell. This may be one of the mechanism of kanamycin ototoxicity.

Animals↗
PubMed1990

[Immunohistochemical demonstration of mycobacterial antigen].

BCG antigen and M. tuberculosis antigen were demonstrated in smear of M. tuberculosis, tissue sections of experimental infected mice and tuberculous patients by immunohistochemical staining. Both acid-fast-HRP-SPA and acid-fast-IGSS double staining methods were tried successfully. Both antigens were present on acid-fast bacilli (AFB). Furthermore, BCG antigen was localized on the mycobacteria cell wall by immunoelectron-microscopic staining. Both antigens were not detected in 19 control specimens of normal tissues and the tissues infected by 8 other species bacilli or fungi except M. leprae and atypical mycobacteria (photochromogens). The rate of positive BCG antigen (69.34%, 95/137) was significantly higher than that of AFB (34.3%, 47/137), (P less than 0.01). The antigens were also found in some AFB free necrotic areas and macrophages. So, immunohistochemical detection of mycobacteria antigens is fairly specific. It is helpful in studying immunopathological changes and in the diagnosis of tuberculosis.

Animals↗
PubMed1990

[Observation of morphological genesis and histochemistry of pulmonary adenocarcinoma in mice].

In the developing process of pulmonary adenocarcinoma in mice induced by N-methyl-N'-nitro-N-nitrosoguanidine, the observations of histological pathology, ultrastructure and the changes of enzyme activity of the lesions related to pulmonary adenocarcinoma were made by light microscopy, transmission electron microscopy and enzyme histochemistry, by sacrificing animals at intervals. The results indicated that there was a series of precancerous lesions before the initiation of adenocarcinoma; that adenoma was a kind of precancerous lesion which might develop into adenocarcinoma; and that adenoma with malignant change might be a focus of early adenocarcinoma. Based on the results of histological pathology, ultrastructure and enzyme histochemistry, a process of the morphological genesis of pulmonary adenocarcinoma in mice was proposed, and the metabolic changes related to various lesions were discussed.

Adenocarcinoma↗
PubMed1989

Immunohistochemical detection of a substance resembling growth hormone-releasing factor in the brain of the rainbow trout (Salmo gairdneri).

We studied the distribution of an immunoreactive substance resembling growth hormone-releasing factor (GRF) in the hypothalamus and pituitary gland of the rainbow trout by immunofluorescence methods. The GRF-like immunoreactive perikaryon was observed in colchicine-treated fish. The majority of GRF-containing neurons were located in the nucleus lateral tuberis; others were located in the caudal part of the preoptic nucleus of the hypothalamus. The GRF-like immunoreactive neuronal processes projected into the pars distalis via the pars nervosa of the pituitary gland. The distribution of the GRF-like immunoreactive substance in the hypothalamus and pituitary gland suggests that GRF plays a physiological role in the regulation of growth hormone release from the pituitary gland of rainbow trout, as it does in mammals.

Animals↗
PubMedDate not supplied

Clinical outcomes in statin treatment trials: a meta-analysis.

OBJECTIVE: To determine the risk of cardiovascular events and death in patients receiving statin treatment for cholesterol regulation. METHODS: Systematic review and meta-analysis of all randomized controlled trials that were published as of April 15, 1997. Primary or secondary prevention trials or regression trials were eligible. MAIN OUTCOME MEASURES: All-cause mortality, fatal myocardial infarction (MI) or stroke, nonfatal MI or stroke, angina, and withdrawal from the studies. Both random- and fixed-effects models were run for the outcomes of interests, and results are expressed as odds ratios (ORs). Sensitivity analyses tested the impact of the study type and duration, statin treatment type, and control arm event rates. Intent-to-treat denominators were used whenever they were available, and the number needed to treat was calculated when appropriate. RESULTS: Seventeen studies (21 303 patients) were included (2 secondary prevention studies, 5 mixed primary-secondary prevention population studies, and 10 regression trials). Treatment groups included lovastatin (t = 5), pravastatin (t = 10), and simvastatin (t = 3). For all-cause mortality, the OR was 0.76 (95% confidence interval [CI], 0.67-0.86) in favor of receiving statin treatment; for fatal MI, the OR was 0.61 (95% CI, 0.48-0.78); for nonfatal MI, the OR was 0.69 (0.54-0.88); for fatal stroke, the OR was 0.77 (95% CI, 0.57-1.04); for nonfatal stroke, the OR was 0.69 (95% CI, 0.54-0.88); and for angina, the OR was 0.70 (95% CI, 0.65-0.76). CONCLUSIONS: Patients who received statin treatment demonstrated a 20% to 30% reduction in death and major cardiovascular events compared with patients who received placebo. This advantage was generally present across study types and statin treatment types and for patients with less severe dyslipidemias. The benefit in clinical outcomes was noticeable as early as 1 year.

Anticholesteremic Agents↗
PubMedDate not supplied

Alphamethrin-impregnated bed nets for malaria and mosquito control in China.

A community-based intervention trial was carried out to evaluate the effectiveness of alphamethrin-impregnated bed nets for control of Plasmodium vivax malaria and its vector in an area of moderate endemicity in southern Henan province, central China in 1990. Malaria incidence was significantly lower in the intervention group than in the comparison group (2.03 vs. 3.57 per 100 person-years at risk). The protective efficacy for malaria incidence was 43%. The prevalence of malaria parasitaemia among children under 10 years old in the intervention group was about one-quarter of that in the comparison group (0.93% vs. 3.25% and 0.71% vs. 1.96% after one and 4 months use of impregnated nets, respectively). Alphamethrin-impregnated bed nets had a mass killing effect on vector mosquitoes. The outdoor person-biting density of Anopheles anthropophagus and A. sinensis decreased by 70.3% and 29.3% respectively. The density of these 2 mosquito species found resting inside treated nets was close to zero. No side effect was found among users of impregnated bed nets. Impregnation with alphamethrin was more effective on polyester than on cotton netting and residual effects lasted at least one year. Use of alphamethrin is less expensive than permethrin and deltamethrin.

Animals↗
PubMedDate not supplied

The effect of DDT spraying and bed nets impregnated with pyrethroid insecticide on the incidence of Japanese encephalitis virus infection.

A retrospective investigation was conducted to evaluate the effectiveness of DDT residual indoor spraying and bed nets impregnated with pyrethroid insecticide for Japanese encephalitis control in southern Henan province, China. DDT residual indoor spraying had no effect on the incidence of Japanese encephalitis, but it was greatly reduced after the introduction of pyrethroid-impregnated bed nets. Only a small effect on outdoor biting densities of Culex tritaeniorhyncus was found, although the number of mosquitoes resting inside bed nets decreased markedly after the introduction of bed net impregnation.

Animals↗
PubMedDate not supplied

The protective effect of bed nets impregnated with pyrethroid insecticide and vaccination against Japanese encephalitis.

A population-based case-control study to evaluate the protective effect of bed nets impregnated with pyrethroid insecticide and of vaccination against Japanese encephalitis was carried out in Gusi county, Henan province, China from June to September 1991; 50 cases and 100 matched controls were studied. Bed nets impregnated with pyrethroid insecticide greatly decreased the risk of infection among children under 10 years old, and vaccine efficacy was 78% (95% CI 16%-94%). We suggest that impregnated bed nets could be used as a quick response during outbreaks of Japanese encephalitis.

Bedding and Linens↗