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Biomedical subjects

P Yang

Publications and source records attributed to P Yang.

At least 163 records · Page 9Linked to original sources
PubMed1999

D-serine added to clozapine for the treatment of schizophrenia.

OBJECTIVE: D-Serine is a full agonist at the glycine site on the N-methyl-D-aspartate (NMDA) receptor. Previous administration of D-serine to schizophrenic patients taking nonclozapine antipsychotics improved positive, negative, and cognitive symptoms, whereas the partial agonist D-cycloserine improved negative symptoms of patients taking conventional antipsychotics but worsened symptoms in clozapine-treated patients. To study the difference between full and partial agonists at the NMDA receptor glycine site, the clinical effects of adding D-serine to clozapine were assessed. METHOD: In a 6-week double-blind trial, 20 schizophrenic patients received placebo or D-serine (30 mg/kg per day) in addition to clozapine. Clinical efficacy, side effects, and serum levels of D-serine were determined every other week. RESULTS: The patients exhibited no improvement with D-serine, nor did their symptoms worsen, as previously reported with D-cycloserine. CONCLUSIONS: The results suggest either that clozapine may have an agonistic effect on the NMDA system or that clozapine-treated patients do not respond to D-serine.

Antipsychotic Agents↗
PubMed1999

Captopril as an antioxidant in lead-exposed Fischer 344 rats.

Recent studies suggest that lead induces oxidative stress in various tissues. Captopril ([2S]-1-[3-mercapto-2-methylpropionyl]-L-proline), an angiotensin-converting enzyme inhibitor, is a well-known antihypertensive agent and is also believed to function as an antioxidant. In the present study the antioxidant effect of captopril on lead-induced oxidative stress was studied in Fischer 344 rats. Their liver, brain and kidneys were assayed for glutathione (GSH), glutathione disulfide (GSSG), malondialdehyde concentrations, and catalase activities. The results from animals treated with captopril were compared to results of control and lead-exposed non-treated groups. The captopril-treated samples showed higher GSH:GSSG ratios in the liver, brain and kidneys, as well as slightly decreased malondialdehyde concentrations. The catalase activity was not significantly affected.

3,4-Methylenedioxyamphetamine↗
PubMed1999

Kinetics of thermal inactivation of penaeus penicillatus acid phosphatase

The kinetics of thermal inactivation of Penaeus penicillatus acid phosphatase have been studied using a kinetic method related to the substrate reaction during irreversible inhibition of the enzyme activity as previously described by Tsou (Adv. Enzymol. Relat. Areas Mol. Biol. (1988) 61, 381-436). The kinetics of thermal inactivation of the enzyme show that the reaction is irreversible. The microscopic rate constants were determined for thermal inactivation of free enzyme and the enzyme--substrate complex. The results show that the presence of substrate has a significant protective effect against thermal inactivation of the enzyme.

Journal Article↗
PubMed1999

Alpha1-antitrypsin deficiency allele carriers among lung cancer patients.

Lung cancer (LC) and chronic obstructive pulmonary lung diseases (COPDs; including emphysema and chronic bronchitis) share a common etiology. Despite the known associations of alpha1-antitrypsin deficiency (alpha1AD) with COPD and COPD with LC, few studies examined the association of alpha1AD alleles and LC. We hypothesize that heterozygous individuals who carry a deficient allele of the alpha1AD gene Pi (protease inhibitor locus) are at an increased risk of developing LC. The Pi locus is highly polymorphic with >70 variants reported. There are at least 10 alleles associated with deficiency in alpha1-antitrypsin. Using an exact binomial test, we compared the alpha1AD carrier rate in 260 newly diagnosed Mayo Clinic LC patients to the reported carrier rate in Caucasians in the United States (7%). alpha1AD carrier status, determined by isoelectric focusing assay, was examined with respect to the history of cigarette smoking, COPD, and histological types. Thirty-two of the 260 patients (12.3%; 95% confidence interval, 8.6-16.9%) carried an alpha1AD allele, which was significantly higher than expected (P = 0.002). Twenty-four of the 32 carriers had allele S, 6 had allele Z, and 2 had allele I. Patients who never smoked cigarettes were three times more likely to carry a deficient allele (20.6%; P = 0.008), although smokers had a higher carrier rate (11.1%; P = 0.025) when compared with the 7% rate. Patients with squamous cell or bronchoalveolar carcinoma had a significantly higher carrier rate than expected (15.9% and 23.8%, P < or = 0.01, respectively). Our preliminary findings suggest that individuals who carry an alpha1AD allele may have an increased risk for developing LC, specifically squamous cell or bronchoalveolar carcinoma.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1999

Macroscopic spectral imaging and gene expression analysis of the early stages of melanoma.

BACKGROUND: The stages of melanocytic progression are defined as atypical (dysplastic) nevus, melanoma in situ, melanoma in the radial growth phase (RGP), melanoma in the vertical growth phase (VGP), and melanoma in the metastatic growth phase (MGP). Melanoma in situ and RGP melanoma often develop in contiguous association with atypical nevi. This frequently poses a problem with respect to their early detection. Furthermore, unlike cells obtained from VGP and MGP melanomas, cells derived from melanoma in situ and RGP melanoma do not proliferate in vitro. Thus, compared to the late stages of the disease, less information is available regarding genes expressed in the early stages. MATERIALS AND METHODS: To determine whether spectral imaging, a recently developed optical imaging technique, can detect melanoma in situ and RGP melanoma arising in melanoma precursor lesions, atypical nevi in patients with a clinical history of melanoma were subjected to noninvasive macroscopic spectral imaging. To determine at what stage in the progression pathway of melanoma genes having important biological functions in VGP and MGP melanomas are activated and expressed, lesions of melanoma in situ were analyzed by immunohistochemistry and in situ hybridization for expression of some of these known molecular and immunologic markers. RESULTS: The present study demonstrates the capability of noninvasive spectral imaging to detect melanoma in situ and RGP melanoma that arise in contiguous association with atypical nevi. Furthermore, the study provides evidence that genes and antigens expressed in VGP and MGP melanoma are also expressed in melanoma in situ. CONCLUSIONS: Because of the dark and variegated pigmentation of atypical nevi, melanoma in situ and RGP melanoma that arise in these melanoma precursor lesions are often difficult to recognize and thus frequently go unnoticed. The application of new optical screening techniques for early detection of melanoma and the identification of genes expressed in the early stages of melanoma development are two important avenues in the pursuit of melanoma prevention. The investigations presented here document that macroscopic spectral imaging has the potential to detect melanoma in its early stage of development and that genes essential for the proliferation and cell adhesion of VGP and MGP melanoma are already expressed in melanoma in situ.

Biomarkers, Tumor↗
PubMed1999

[The clinical application of triamcinolone to accelerate soft tissue expansion].

OBJECTIVE: To speed up the expansion procedure. METHODS: Triamcinolone was injected during tissue expansion in 26 cases. RESULTS: The study proved that triamcinolone shortened the injection interval to 32 +/- 6 hours. The mean time of full expansion was shortened to 20 +/- 5 days in the experimental group. The injection interval and mean time of full expansion were 6 +/- 2 days and 42 +/- 8 days respectively in the control group (P < 0.01). The immediate retraction ratios of expanded skin of the two groups were 17% and 26% respectively. CONCLUSION: This new method is feasible in clinical application.

Adolescent↗
PubMed1999

[Culture of chondrocytes using allogenous acellular cartilaginous matrix].

OBJECTIVE: To observe the effect of chondrocyte culture with natural ECM made from allogenous acellular cartilage. METHODS: The allogenous acellular cartilaginous matrix was used as a scaffold in chondrocyte culture in vitro, comparing with the acellular perichondrium. The growth and regeneration of the chondrocytes in vitro were observed. RESULTS: The chondrocytes seeded on the acellular cartilaginous matrix grew well while the chondrocytes on the acellular perichondrium matrix grew poorly. CONCLUSION: The surface condition of the scaffold has a notable influence on the growth of the cells. The allogenous acellular cartilaginous matrix may provide a suitable condition for chondrocytes, and it has the possibility to be developed as a natural scaffold for tissue engineering.

Animals↗
PubMed1999

Immunological studies on the cellular phenotype involved in corneal allograft rejection.

OBJECTIVE: To investigate the cellular phenotype involved in corneal allograft rejection using wholemounts analysis. METHODS: Corneal transplantation was performed between Sprague Dawley (SD) and Wistar rats. Corneal wholemounts were prepared from control rats and those after corneal transplantation on day 7 and 12. Immunohistochemical stain was performed on these wholemounts using monoclonal antibodies to transforming growth factor beta 1(TGF-beta 1), CD3, CD4, CD8, B lymphocytes, macrophages, dendritic cells and major histocompatibility complex (MHC) class II antigen. RESULTS: Corneal allograft rejection started on day 7 and reached its maximum from 10 to 14 days after corneal transplantation. Presence of TGF-beta 1-, CD3-, CD4-, CD8-, MHC class II-positive cells, macrophages and dendritic cells were noted at the limbus of both SD rats and Wistar rats. No positive cell was present in the central cornea of normal rats. All positive cells but B lymphocyte were noted in large numbers in the cornea after corneal allograft transplantation. Marked staining for TGF-beta 1 was noted during graft rejection. CONCLUSION: The corneal wholemounts technique provides a good visualization for the cellular phenotype involved in corneal allograft rejection. A variety of cells including TGF-beta 1, CD3, CD4, CD8, MHC class II antigen positive cells, macrophages and dendritic cells are involved in corneal allograft rejection. TGF-beta 1-positive cell might be an important immunosuppressive factor after corneal transplantation and also involved in the induction of fibrosis.

Animals↗
PubMed1999

[Study of the local anatomy and clinical practice about rhytidectomy of nasolabial fold].

OBJECTIVE: A technique is introduced to improve the operative result of rhytidectomy of the nasolabial fold. METHODS: Regional anatomy was studied on 10 adult cadavers together with histological examinations of tissue sections to investigate the formation mechanism of the nasolabial fold. 13 patients were operated on using a new technique of nasolabial fold rhytidectomy. RESULTS: Prolonged and repeated movements of the facial mimetic muscles produce a shearing force between the skin-subcutaneous tissue and the SMAS-mimetic muscles, causing relative motion of adjacent tissues with different structure at the site of the nasolabial fold, thus producing the nasolabial fold. In clinical application of the finding, the nasolabial folds of 13 patients were corrected with remarkable early and long-term results postoperatively. CONCLUSION: The operation should be performed between SMAS and the subcutaneous tissue. SMAS should be incised along the zygomatic major muscle. The fibro-fatty zygomatic pad should be replaced anatomically and the zygomatic ligament be reconstructed.

Adult↗
PubMed1999

[Experimental study on antiendotoxin effect of extracts from Artemisia annua L].

OBJECTIVE: To explore the antiendotoxin effect of extracts from Artemisia annua (AA) and qinghaosu (QHS). METHOD: LPO and SOD in chondriosome, ACP in lysosomes, tumor nicrosis factor-alpha(TNF-alpha) and endotoxin in plasma, and P450 concentration in hepatic microsome of rats were determined. Mortality of endotoxemic mice and histomorphology were observed. RESULT: LPO, ACP, endotoxin, TNF-alpha and P450 content were decreased with AA and QHS. SOD activity was increased with AA and QHS. At the same time, mortality was decreased. Histomorphology of lysosomes and chondriosome of rats were protected from endotoxin. CONCLUSION: AA and QHS possess an antiendotoxin effect.

Animals↗
PubMed1999

[Surface modification of low temperature isotropic pyrolytic carbon artificial heart valve material].

In this study, nitrogen ion implantation and titanium oxide film synthesized by ion beam enhanced deposition were adopted to treat low temperature isotropic pyrolytic carbon (LTIC). The chemical composition and valence state of the modified layer were determined by X-ray photoelectron spectroscopy (XPS) and Auger eletron spectroscopy (AES). The electric resisitance and the surface energy were measured by the four-probe system and the contact angle method respectively. The blood compatibility of the modified LTIC was evaluated by clotting time measurement and platelet adhesion test. The results showed that carbon-nitride was formed on the LTIC surface after N+ ion implantation, which had some effect on the improvement of blood compatibility, and a significant improvement of blood compatibility of LTIC coated by TiO2-x film was verified.

Animals↗
PubMed1999

[A new algorithm for direct volume rendering of medic image series].

In this paper, a new algorithm based on Voxel Model is proposed. This algorithm combines the advantages of surface rendering and direct volume rendering. In the process of 3D reconstruction, OpenGL graphic standard and hardware accelerator can be used. By doing so, better reconstruction, result and fast speed can be achieved. Also, it is simple to turn this algorithm into programs.

Algorithms↗
PubMed1999

[Visible human data set and it's application].

The Visible Human Project is an outgrowth of the NLM's 1986 Long-Range Pian. It is creating a complete, anatomically detailed, three-dimensional representations of the male and female human body. This paper makes a brief description about VHP and it's significance, how to get VH data set and how to use it.

Adult↗
PubMed1999

[Assay of sensitivity of Plasmodium falciparum to chloroquine, amodiaquine, piperaquine, mefloquine and quinine in Yunnan province].

AIM: To determine the sensitivity of P. falciparum to chloroquine, amodiaquine, piperaquine, mefloquine and quinine in Yunnan Province of China in 1992-1995. METHODS: Rieckmann's in vitro microtechnigue was used. The sensitivity of P. falciparum was tested to the above-mentioned antimalarials. RESULTS: The resistance rates of isolates of P. falciparum from the south, southeast and the west part of Yunnan to chloroquine and amodiaquine were 96.7% (29/30), 78.9% (30/38), 95.7% (22/23) and 100% (30/30), 85.3% (29/34), 8/9, respectively, with their corresponding ID50 of 125 nmol/L, 136 nmol/L and 176 nmol/L, and 52 nmol/L, 64 nmol/L and 72 nmol/L, respectively. All the isolates were sensitive to quinine and their ID50 were 480 nmol/L, 352 nmol/L, 608 nmol/L, respectively. The resistance rates of P. falciparum from the south part and southeast part of Yunnan to piperaquine were 96.4% (27/29), 72.9 (27/37), respectively, their ID50 were 320 nmol/L and 228 nmol/L; all the cases were sensitive to mefloqine, their ID50 were 68 nmol/L and 88 nmol/L. CONCLUSION: P. falciparum generally produces resistance to chloroquine, amodiaquine and piperaquine in Yunnan Province; the degree of resistance to chloroquine of P. falciparum from the west part of Yunnan were higher than the P. falciparum from the southeast part of Yunnan; all the isolates were sensitive to mefloquine and quinine in this region.

Amodiaquine↗
PubMed1999

[Soluble IL-2 receptor levels in patients with Graves' ophthalmopathy].

OBJECTIVE: Soluble interleukin-2 receptor (sIL-2R) levels in sera with Graves' ophthmopathy was investigated for its relationship to the clinical manifestations and therapeutic effects. METHODS: sIL-2R levels were measured in sera of 41 patients with Graves' ophthalmopathy which had not yet received specific treatment for their ophthalmopathy and euthyroid during the entire study period and 49 normal subjects. RESULTS: In untreated patients, the mean levels of sIL-2R were significantly higher than those in the normal subjects (P < 0.001). There was no difference in the levels of sIL-2R between patients with hyperthyriod Graves' ophthalmopathy and those with enthyroid Graves' ophthalmopathy. The levels of sIL-2R in patients with response for corticosteoids treatment were significantly higher than that in patients with non-response for corticosteoids treatment (P < 0.001), but there were no differences between the each class present in the NOSPECS classification of ophthalmopathy. 12 patients with response for corticosreoids had lower sIL-2R levels After 3-month treatment than pertreatment. CONCLUSION: These results suggested that elevated sIL-2R levels in patients with Graves' ophthalmopathy may be derived from ophthalmopathy itself, e.g. intra-orbital activated lymphocytes, and serve as a useful parameter to evaluate clinical activity score and predict value of corticosteoids treatment outcome.

Adult↗
PubMed1999

[Development and evaluation of a system for pulse generation and signal processing control in a plasma atomic fluorescence spectrometer with hollow cathode lamp as excitation source].

A Z80 processor was replaced with a 386 microcomputer to control pulse generation for hollow cathode lamp and fluorescence signal processing in a Baird Plasma AFS-2000 atomic fluorescence spectrometer. An interface board was designed for control purpose. The system was evaluated with detection limits, relative standard deviations and linear regression coefficients of 15 elements, which were in good agreement with the corresponding values in the manufacturer's manual. With the higher-level microprocessor in the system, the performance of the instrument was improved.

English Abstract↗