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Biomedical subjects

P Tu

Publications and source records attributed to P Tu.

At least 19 recordsLinked to original sources
PubMed2004

DNA-based prenatal diagnosis in a Chinese family with xeroderma pigmentosum group A.

BACKGROUND: Xeroderma pigmentosum (XP) is a group of autosomal recessive diseases characterized by hypersensitivity to ultraviolet rays. Among its eight complementation groups, XP group A (XPA) is the most severe type. The XPAC gene has been identified as the defective gene in XPA patients. OBJECTIVES: To examine genomic DNA from a Chinese family with XPA, to determine the XPAC mutation and, after genetic counselling, to undertake DNA-based prenatal diagnosis in a subsequent pregnancy. METHODS: Fetal DNA was extracted from amniotic fluid and used to amplify exon 5 of XPAC containing the potential mutation. Direct sequencing and restriction endonuclease digestion were used for prenatal diagnosis. RESULTS: We identified a homozygous nonsense XPAC mutation of 631C-->T, which results in an R211X mutation in XPA protein, in the proband. Both her parents are heterozygous. Prenatal diagnosis demonstrated a heterozygous sequence predicting an unaffected child, and a healthy girl was born. CONCLUSIONS: These data provide the first example of a DNA-based prenatal test for genodermatosis in China.

Child, Preschool↗
PubMed2001

Preparative isolation and purification of acteoside and 2'-acetyl acteoside from Cistanches salsa (C.A. Mey.) G. Beck by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was applied to the separation and purification of phenylethanoid glycosides (PhGs) acteoside and 2'-acetylacteoside from Cistanches salsa (C.A. Mey) G. Beck with a quaternary two-phase solvent system composed of ethyl acetate-n-butanol-ethanol-water (4:0.6:0.6:5, v/v). HPLC analyses of the CCC fractions revealed that the two main PhGs were over 98% purity. Their chemical structures were identified by 1H NMR, 13C NMR and MS.

Chromatography, High Pressure Liquid↗
PubMed2001

Pyrolytic characteristics of microalgae as renewable energy source determined by thermogravimetric analysis.

Two kinds of autotrophic microalgae, Spirulina platensis (SP) and Chlorella protothecoides (CP) were pyrolyzed at the heating rates of 15, 40, 60 and 80 degrees C/min up to 800 degrees C in a thermogravimetric analyzer to investigate their pyrolytic characteristics. Three stages (dehydration, devolatilization and solid decomposition) appeared in the pyrolysis process. SP and CP mainly devolatilized at 190-560 degrees C and 150-540 degrees C, respectively. A total volatile yield of about 71% was achieved from each microalga. As the heating rate increased, a lateral shift to higher temperatures was observed in their thermograms, and the instantaneous maximum and average reaction rates in the devolatilization stage were increased while the activation energy was decreased. The value of activation energy for CP pyrolysis was 4.22-5.25 x 10(4), lower than that of SP (7.62-9.70 x 10(4)), and the char in final residue of CP was 14.00-15.14%, less than that of SP by 2-3%. This indicated that CP is preferable for pyrolysis over SP. The experimental results may provide useful data for the design of pyrolytic processing systems using planktonic microalgae as feedstock.

Bioelectric Energy Sources↗
PubMed2001

A comparison of adapalene gel 0.1% vs. tretinoin gel 0.025% in the treatment of acne vulgaris in China.

AIM: To compare the efficacy, safety and tolerability of adapalene gel 0.1% vs. tretinoingel 0.025% in a Chinese patient population. BACKGROUND: Although acne vulgaris is a common problem among Asians and Asian-Americans, little has been published on the specific manifestations, sequelae, and treatment-responsiveness of this disorder in Asian skin types. Since Asian skin types tend to be more highly pigmented than those of white people of European descent, many Asians share the predisposition toward postinflammatory hyperpigmentation seen in Africans, African-Americans and other dark-skinned peoples. It is generally assumed that the efficacy and safety of topical retinoids is the same in Asians as in white people. Tretinoin has been available in China for decades; adapalene became available in 1998. METHODS: A total of 150 patients with grade II-III acne vulgaris seen at three dermatology clinics were randomized to 8 weeks of daily treatment with either adapalene gel 0.1% or tretinoin gel 0.025%. Counts of total lesions, inflammatory lesions and non-inflammatory lesions were made at baseline and again at treatment weeks 2, 4, 6 and 8. Global assessment ratings, based on percent lesion reduction from baseline were also made. Erythema, burning, pruritus, scaling and dryness were rated on a 0-3 severity scale. RESULTS: A total of 139 patients completed the efficacy evaluation, and 144 patients completed the safety evaluation. Both adapalene and tretinoin produce dramatic reductions in total, inflammatory and non-inflammatory lesion counts, in the range of 69-74% on average. More than 70% of patients in both groups had complete clearance or marked improvement. In general, irritation was mild, but was both more common and more severe in the tretinoin group vs. the adapalene group. No systemic side effects were seen. CONCLUSIONS: Adapalene offers comparable efficacy to tretinoin, but is less irritating. It represents a good alternative for the treatment of mild to moderate acne vulgaris in Chinese patients.

Acne Vulgaris↗
PubMed2001

Adapalene gel 0.1%: effective and well tolerated in the topical treatment of acne vulgaris in Chinese patients.

Acne vulgaris is a common dermatologic disease in Asian populations, as well as in Caucasians. Our objective was to evaluate the safety and efficacy of adapalene gel 0.1% in comparison with tretinoin gel 0.025% in Chinese patients with acne vulgaris. We used an 8-week, multicenter, randomized, controlled, investigator-masked, parallel group design study of adapalene gel 0.1% and tretinoin gel 0.025% in 150 Chinese patients with mild-to-moderate acne vulgaris. Our results showed that adapalene gel 0.1% had efficacy equivalent to tretinoin gel 0.025% against acne lesions in Chinese patients, with a more acceptable tolerability profile.

Acne Vulgaris↗
PubMed1999

[Studies on chemical constituents and pharmacological effects of the stem of Cynomorium songaricum Rupr].

OBJECTIVE: In order to exploit the medicinal resources and provide a scientific evidence for the clinical use and quality of Cynomorium songaricum control, the chemical constituents and pharmacological effects of the stem of the plant were studied preliminarily. METHOD: The chemical constituents were studied by spectral analysis and chemical method. The pharmacological effects were studied by an experiment on the defecation and deficiency of kidney function. RESULT AND CONCLUSION: Seven compounds were isolated from the stem of C. songaricum and identified as beta-sitosterol(I), palmitic acid (II), ursloic acid (III), daucosterol (IV), (-)-catechin (VI), naringenin-4'-O-pyranogluoside (VII) and succinicyacid (XII). Compounds VI and XII were isolated from this species for the first time. The pharmacological results show that the different extracts facilitate catharsis and replenish the deficiency of kidney yang.

Animals↗
PubMed1999

[Morphological and histological studies of Herba Boschniakiae].

This paper deals with the morphological characters of the plants and drugs, and the histological characters of the stems of Herba Boschniakiae (Boschniakia rossica). This results provide authentic methods for the identification of Herba Boschniakiae.

Drug Contamination↗
PubMed1999

[Pharmacognostical studies on radix Glehniae (Glehnia littoralis)].

OBJECT: To identify the roots of Glehnia littoralis Fr. Schmidt ex Miq., and compare the chemical constituents of the root skin and the roots with no skin. METHODS: The roots were identified by morphological and microscopic identification and TLC. RESULTS: The characteristics of the secretory canal, ray and starch grain can be used to identify the histology and powder of the roots. The chemical constituents of the root skin and the roots with no skin are similar. CONCLUSION: The characteristics of the morphology, histology and powder can be used to identify the roots of Glehnia littoralis (Radix Glehniae).

Apiaceae↗
PubMed1998

Expression of platelet-derived growth factor B-chain and platelet-derived growth factor beta-receptor in fibroblasts of scleroderma.

Scleroderma is a fibrotic disease occurring in a localized or systemic form. The pathogenesis of scleroderma remains poorly understood. Recent studies revealed that various cytokines and growth factors were involved in the development of scleroderma fibrosis. Platelet-derived growth factor (PDGF) is a potent growth factor for mesenchymal cells, especially fibroblasts. It can promote fibroblasts proliferation, enhance extracellular matrix synthesis. It is also a chemoattractant to fibroblasts. To better understand the role of PDGF in pathogenesis of scleroderma, we performed both in vivo studies on the expression of PDGF beta-receptor protein in scleroderma tissue and in vitro studies on the expression of PDGF B-chain and PDGF beta-receptor mRNA in cultured fibroblasts derived from both lesions of scleroderma and normal skin. Immunohistochemistry staining showed that PDGF beta-receptor expression was greatly elevated in the dermis of scleroderma lesion whereas PDGF beta-receptor were expressed at low levels in normal skin. Northern blot analysis showed that cultured fibroblasts from scleroderma had higher expression of PDGF B-chain and PDGF beta-receptor mRNA than those from normal control. Two PDGF B-chain mRNA transcripts, 2.8 and 4.0 kb, were expressed. The 2.8 kb transcripts which had more efficient translation ability was the more predominantly expressed one. These results indicate that PDGF B-chain/PDGF beta-receptor signal pathway might be involved in the development of fibrosis in scleroderma, and that the 2.8 kb PDGF B-chain mRNA transcript may be the main modulation gene.

Adult↗
PubMed1998

[Histological studies on the roots of twelve species of Sect. Microdiscus and Sect. Adenophora of the genus Adenophora].

This paper reports the root structures of Adenophora lamarkii Fisch, A. hunanensis Nannf., A. hunanensis Nannf. subsp. huadungensis Hong, A. trachelioides Maxim., A. trachelioides Maxim. subsp. giangsuensis Hong, A. remotiflora (Sieb. et Zucc.) Miq. derived from Sect. Microdiscus of the Genus Adenophora, and A. stenanthina (Ledeb.) Kitagawa, A. stenanthina (Ledeb.) Kitagawa subsp. xifengensis P. F. Tu et Y. S. Zhou, A. liliifolioides Pax et Hoffm., A. capillaris Fisch., A. tetraphylla Fisch., A. triphylla (Thunb.) A. DC. derived from Sect. Adenophora of the Genus Adenophora. Based on the histological studies of 23 species, 5 subspecies and 2 varieties of the Genus Adenophora, a Key of histological characters is given.

Campanulaceae↗
PubMed1998

[Histological studies on the roots of eighteen species of sect. microdiscus of the genus Adenophora].

The Chinese materia medica "Nanshasheng" (Radix Adenophorae) specified in Chinese Pharmacopoeia (1995) is the dried root of Adenophora tetraphylla (Thunb.) Fisch. or A. stricta Miq. (Fam. Campanulaceae). Results of an investigation on the botanical origin of the drug showed that the roots of 30 species (subspecies, varieties) of the genus Adenophora are also used in certain districts in China. Thus, it is necessary to study and compare the histological characters of these roots. In this paper, the root structure of 18 species from Sect. Microdiscus are reported, viz. Adenophora brevidiscifera Hong, A. coelestis Diels, A. stricta Miq., A. stricta Miq. var. qinglongshanica P. F. Tu et G. J. Xu, A. stricta Miq. var. nanjingensis P. F. Tu et G. J. Xu, A. stricta Miq. subsp. henanica P. F. Tu et G. J. Xu, A. stricta Miq. subsp. sessilifolia Hong, A. longipedicellata Hong, A. gmelinii (Spreng.) Fisch., A. polyantha Nakai, A. micrantha Hong, A. stenophylla Hemsl., A. potaninii Korsh., A. bockiana Diels, A. wawreana Zahlbr., A. tricuspidata (Fisch. ex Roem. et Schult.) A. DC., A. pereskiifolia (Fisch. ex Roem. et Schult.) G. Don and A. divaricata Franch. et Sav.. According to the presence, arrangement and thickening of cell walls of sclerified cork cell (SCC) in cork tissue and the rate of secondary and anomalous structures, the histological structures of Adenophora roots are classified into types A, B and C. In type A, SCC are arranged in ring shape. Type A can be further classified into subtypes A1 and A2. Only the outer and anticlinal walls of SCC are thickened in subtype A1, and all cell walls of SCC are thickened in subtype A2. In type B, SCC are arranged scatteredly, not in ring shape. In type C, there is no SCC. Type C can be classified into subtypes C1, C2 and C3. In type C1, the secondary structure occupies more than 50% of the root diameter. In type C2, the anomalous structure is more than 50% of the root diameter, and the anomalous vascular bundles are in band form. The anomalous structure occupies more than 50% of the root diameter in subtype C3, and the anomalous vascular bundles are branched.

Campanulaceae↗
PubMed1998

[Identification of Radix and Rhizoma Rhei by UV and TLC].

This paper deals with the identification of radix and rhizoma of 24 species (varieties) of Genus Rheum by UV and TLC. This results provide authentic methods for the identification of Radix and Rhizoma Rhei.

Chromatography, Thin Layer↗
PubMed1997

Neurofilaments and orthograde transport are reduced in ventral root axons of transgenic mice that express human SOD1 with a G93A mutation.

Mice engineered to express a transgene encoding a human Cu/Zn superoxide dismutase (SOD1) with a Gly93 --> Ala (G93A) mutation found in patients who succumb to familial amyotrophic lateral sclerosis (FALS) develop a rapidly progressive and fatal motor neuron disease (MND) similar to amyotrophic lateral sclerosis (ALS). Hallmark ALS lesions such as fragmentation of the Golgi apparatus and neurofilament (NF)-rich inclusions in surviving spinal cord motor neurons as well as the selective degeneration of this population of neurons were also observed in these animals. Since the mechanism whereby mutations in SOD1 lead to MND remains enigmatic, we asked whether NF inclusions in motor neurons compromise axonal transport during the onset and progression of MND in a line of mice that contained approximately 30% fewer copies of the transgene than the original G93A (Gurney et al., 1994). The onset of MND was delayed in these mice compared to the original G93A mice, but they developed the same neuropathologic abnormalities seen in the original G93A mice, albeit at a later time point with fewer vacuoles and more NF inclusions. Quantitative Western blot analyses showed a progressive decrease in the level of NF proteins in the L5 ventral roots of G93A mice and a concomitant reduction in axon caliber with the onset of motor weakness. By approximately 200 d, both fast and slow axonal transports were impaired in the ventral roots of these mice coincidental with the appearance of NF inclusions and vacuoles in the axons and perikarya of vulnerable motor neurons. This is the first demonstration of impaired axonal transport in a mouse model of ALS, and we infer that similar impairments occur in authentic ALS. Based on the temporal correlation of these impairments with the onset of motor weakness and the appearance of NF inclusions and vacuoles in vulnerable motor neurons, the latter lesions may be the proximal cause of motor neuron dysfunction and degeneration in the G93A mice and in FALS patients with SOD1 mutations.

Age of Onset↗
PubMed1997

[Microscopic identification of the powder of roots of genus Adenophora: II. The roots of Sect. Remotiflorae and Sect. Adenophora].

This paper deals with the microscopic characteristics of the powder of the roots of 11 species and subspecies of Genus Adenophora. The results show that Sect. Basiphyllae, Sect. Pachydiscus, Sect. Remotiflorae and Sect. Adenophora can be identified based on the amount and thickness of the wall as well as the characteristics of the pit of sclerified cork cells, and 29 species, subspecies and varieties can be identified based on the amount, shape and thickness of the walls of the sclerified cork cells, the diameter and pit of the vessels, the number and shape of the secretion of the laticifers, and the number of inulin crystals.

Magnoliopsida↗
PubMed1997

[Fat soluble constituents of the leaves of Vaccinium bracteatum Thunb].

Four compounds were isolated from the fat soluble fraction of the leaves of Vaccinium bracteatum and identified as friedelin (I), epifriedelinol (II), beta-sitosterol(III) and ursolic acid(IV) by IR, NMR and MS. Compound III and IV are isolated from the leaves of this plant for the first time.

Drugs, Chinese Herbal↗
PubMed1997

Acceptance, efficacy, and side effects of Norplant implants in four counties in north China.

This report attempts to present a comprehensive analysis of the acceptability, side effects, and efficacy of Norplant as used in rural areas, based on a field experiment conducted in four counties in Hebei and Shandong Provinces, China. The initial acceptance of Norplant was relatively high but waned after the first year in three of the four counties. Compared with clinical trials, the current study shows a lower prevalence but similar patterns of side effects. The pregnancy rate during the first two years of use is similar to that found in large-scale clinical trials conducted in China, but discontinuation due to other reasons is lower. A three-level logistic regression analysis shows significant variation in the probability of discontinuation due to side effects across counties. It also indicates an increase in the conditional probability of discontinuation with the duration of use. Whereas introducing Norplant and achieving a very low failure rate and high continuation rate in rural areas is feasible under diverse socioeconomic conditions, the results vary significantly across different areas. Particular attention should be paid to the local factors that may affect results.

Adult↗