Search PubMed⌕ Search

Biomedical subjects

S Luo

Publications and source records attributed to S Luo.

At least 73 records · Page 4Linked to original sources
PubMed2000

[Aluminum forms in acid sulfate soils].

With the method of sequential extraction, the extractable noncrystalline aluminum in Acid Sulfate Soils was fractionized into exchangeable Al (ExAl), absorbed inorganic hydroxy-Al(HyAl), organic complexed Al(OrAl), Fe oxide bound Al (DCBAl), interlayered Al(InAl) and noncrystalline aluminosilicate(NcAl) with average of 1.79, 2.51, 4.17, 4.14, 4.31 and 8.66 g Al2O3.kg-1, respectively. In actual Acid Sulfate Soils, the amount of different forms Al followed the order of NcAl > OrAl > InAl > DCBAl > ExAl > HyAl, but in potential acid sulfate soils, NcAl > InAl > DCBAl > HyAl > OrAl > ExAl. The average of the total extractable noncrystalline Al was 35.57 g Al2O3.kg-1, which covered 25.04% of the total amount of Al in Acid Sulfate Soils. The characteristic of extractable noncrystalline Al in Acid Sulfate Soils was the high proportion of active aluminum, such as ExAl, HyAl and OrAl. All forms of Al were closely related to the corresponding properties and ecological characteristics of Acid Sulfate Soils. The strong acid environment of actual Acid Sulfate Soils induced over-released Al, which transformed to active Al and resulted in Al toxicity.

Aluminum↗
PubMed2000

[Clinical study in treating type 2 diabetes mellitus according to liver in TCM].

OBJECTIVE: To explore the clinical effect of Danzhi Xiaoyao powder (DZXY) in treating type 2 diabetes mellitus (DM) according to Liver in TCM. METHODS: Fifty-one type 2 DM patients were randomly divided into the treated group and the control group, 31 patients of the treated group were treated with conventional and DZXY therapy, while 20 patients in the control were treated with conventional therapy alone. Before and after treatment for 3 months, the levels of fasting blood glucose (FBG), fasting insulin, glycosylated hemoglobin (HbA1c), blood cholesterol (CH) and triglycerides (TG) were examined in all the patients. RESULTS: By the end of 3 months, the effect in treating type 2 DM in the treated group was better than that in the control group (P < 0.05). Compared with those before treatment in each group and those of the control, the levels of FBG, fasting insulin, HbA1c after DZXY treatment were reduced (P < 0.05), but levels of CH and TG in all groups had no significant difference. CONCLUSION: DZXY could soothe the Liver to relieve depression, which is effective in treating type 2 DM and could improve the symptoms of DM patients.

Aged↗
PubMed2000

[Effect of hydroxyurea combined with interferon-alpha on growth and apoptosis-related oncogene expression of K562 cells].

OBJECTIVE: To observe the effect of hydroxyurea (HU) alone and in combination with interferon-alpha (IFN-alpha) on the cell growth and cell death, and the related oncogene expression of chronic myelogenous leukemia (CML) cell line, K562 cells. To further investigate the molecular basis of combination therapy on CML by chemotherapeutants combined with cytokines. METHODS: The proliferation and viability of K562 cells were detected by cell-counting and trypan blue dye exclusion test. The levels of bcr-abl, bax and c-myc gene expression in K562 cells incubated for 48 hours were examined using RT-PCR technique. RESULTS: proliferation was suppressed and cell death process was accelerated by both HU and HU combined with IFN-alpha. HU significantly inhibited bcr-abl gene expression and increased bax gene expression level (both P < 0.05 as compared with that of control). Furthermore, IFN-alpha dose-dependently enhanced the regulatory effects of HU on bcr-abl and bax gene expression. HU alone and in combination with IFN-alpha suppressed slightly c-myc gene expression. CONCLUSIONS: Both HU and HU combined with IFN-alpha can inhibit cell proliferation and promote cell death or apoptotic cell death by regulating the expression levels of the genes relating to cell proliferation and apoptosis. The molecular mechanism of HU and IFN-alpha synergistically acting on leukemic cells is further elucidated from the expression level of the related genes which control the balance of survival and death or apoptosis of the cells.

Apoptosis↗
PubMed2000

[Effects of IFN-alpha combined with IL-6 on cell growth and related genes expression and apoptosis of bone marrow cells from CGL patients].

OBJECTIVE: To investigate the effects of interferon-alpha (IFN-alpha) and IFN-alpha combined with interleukin-6 (IL-6) on cell growth and bcr/abl, bcl-2 and c-myc genes expression in the bone marrow mononuclear cells (MNC) from chronic granulocytic leukemia (CGL) patients. METHODS: MNCs were cultured in liquid medium at the presence of IFN-alpha (200 U/ml) or IFN-alpha (200 U/ml) plus IL-6 (100 ng/ml). The viable cells were counted and the expression levels of beta-actin, bcr/abl, bcl-2 and c-myc genes were quantitatively detected by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: The cell growth was markedly inhibited by IFN-alpha, but the extent of the inhibition was slightly decreased when IFN-alpha combined with IL-6. The expression levels of bcr/abl and bcl-2 gene were reduced by IFN-alpha or IFN-alpha plus IL-6. The expression of c-myc gene was inhibited by IFN-alpha but promoted by IL-6. CONCLUSIONS: Both IFN-alpha and IFN-alpha plus IL-6 can inhibit the expression of anti-apoptosis genes, and modulate the expression of c-myc. It is the possible mechanism of IFN-alpha therapy for CGL in chronic phase.

Adolescent↗
PubMed2000

[Establishment and application of a computerized radiography cephalometrics system].

We have developed a new-typed computerized radiography cephalometrics and prediction system. It includes cephalometrics, growth prediction, orthopedics/orthodontics prediction and profile prediction. In this study, 47 lateral cephalograms were randomly selected to process a reliability test. The results showed the two groups were in agreement on all of the 25 measurement index. The system is easier, quicker and less prone to error than traditional cephalometrics approach. It is convenient for orthodontists.

Cephalometry↗
PubMed2000

[Circadian rhythm changes of the levels of endogenous insulin in growing rat condylar cartilage after functional mandibular protrusion].

OBJECTIVE: In order to determine which time of the day is best to wear functional appliances in clinic, the author investigates the circadian rhythm of the level of endogenous Insulin in growing rat condylar cartilages and the changes after functional mandibular protrusion in daytime (8:00-20:00) or nighttime (20:00-8:00). METHODS: 72 4-week-old SD rats were divided equally and randomly into experimental and control groups, and the rats in experimental groups were put on the functional appliance in daytime (8:00-20:00) or nighttime (20:00-8:00). After 7 days, all rats were sacrificed at 0:00, 4:00, 8:00, 12:00, 16:00, 20:00 in a day. Radioimmunoassay methods were used to detect the levels of endogenous insulin in growing rat condylar cartilages. RESULTS: 1. The levels of endogenous insulin in the growing rat condylar cartilage displayed a significant circadian rhythm. The acrophase was about 12:13. 2. The circadian rhythm still existed after the rats had been put on the functional appliance. Both mesor and amplitude were significantly higher in the experimental groups than in the control group 3. The levels (both mesor and amplitude) of endogenous insulin in the condylar cartilage were significantly higher in the daytime-forced group than in the nighttime-forced group. CONCLUSION: 1. The growth and remodeling of the condylar cartilage in the growing rats shows significant circadian rhythm. The most active period of chordrocyte proliferation may occur during the daytime. 2. The circadian rhythm still exists after the rats have been put on the functional appliances. 3. Compared with nighttime appliance wearing, daytime appliance wearing may be more conductive to cell proliferation, so it may be more effective to stimulate the growth and remodeling of condylar cartilage in the growing rat. 4. Related to human beings, these data suggest that the best period for patients to wear the functional appliances might be from 20:00 pm to 8:00 am of the next day.

Animals↗
PubMed2000

[A study on the intrinsic compensative mechanism of craniofacial soft and hard tissue structures of Uygur adults with normal occlusion].

OBJECTIVE: To study the intrinsic compensative mechanism of craniofacial soft and hard tissue structures of Uygur adults with normal occlusion and establish standard cephalometric values to evaluate craniofacial soft and hard tissue structures of normal Uygur adults. METHODS: Lateral cephalometric radiographs of 93 Uygur adults with normal occlusion (43 men and 50 women) were evaluated with the same standard. Their age ranged from 18 to 25 years old, and they had normal and well-balanced faces without receiving any orthodontic treatment. Based on the study of craniofacial soft and hard tissue structures with normal occlusion, the horizontal tendency, the vertical tendency pattern and the medial pattern of craniofacial soft and hard tissue structures were compared, and the intrinsic compensative mechanism in the inner structures of the horizontal and the vertical tendency patterns was investigated. Finally 21 indexes were analysed by mean squar deviation and Newman-Keuls test. RESULTS: The obvious compensative changes in the horizontal and vertical tendency patterns were found in teeth, skeleton and soft-tissues. 1. When the horizontal tendency was compared with the medial pattern, the value of ODI and angles of FH-NA and FH-NB increased (P < 0.01), while the angle of SN-PP decreased (P < 0.01). It showed that the anterior maxilla rotated in the counter-clockwise direction, and the anterior mandible rotated in the clockwise direction. The angle of U1-L1 increased (P < 0.01), which meant that the inclination of anterior teeth decreased. 2. When the vertical tendency was compared with the medial pattern, the value of ODI decreased (P < 0.01), while the height of ANS-Me, U1-PP, L1-MP, and the thickness of LL-SnPg increased (P < 0.01); The angle of L1-MP decreased (P < 0.05), while the length of Sn-Stms increased (P < 0.05). These results showed that there was an obvious positive relationship between hard and soft tissues. The soft tissue thickness could compensate the changes of hard tissues to keep the facial patterns harmony. CONCLUSION: Normal occlusion depends on the homeostasis of teeth, skeleton and soft tissues, but doesn't only depend on the normal craniofacial soft and hard tissue structures respectively. The intrinsic compensative mechanism plays an important role in forming normal occlusion, therefore, doctors should choose the best treatment to obtain optimal individual intrinsic compensative mechanism and achieve an optimal balance between the craniofacial structures and the occlusion.

Adolescent↗
PubMed2000

[An cephalomectric study on craniofacial structures of Uygur adults with normal occlusion in Xinjiang autonomous region].

OBJECTIVE: To study craniofacial structures of Uygur adults with normal occlusion and establish the standard cephalometric values to evaluate the craniofacial soft and hard tissue structures of normal Uygur adults. METHODS: Lateral cephalometric radiographs of 93 Uygur adults with normal occlusion (43 men and 50 women) were evaluated with the same standard. Their age ranged from 18 to 25 years old, and they had normal and well-balanced faces without receiving any orthodontical treatment. The lateral cephalogram of each normal adult was traced digitized and measured by the same computer system, then the indexes of craniofacial structures were analyzed by multifactor cluster analysis. 18 typical items were chosen to analyze the characters of the craniofacial structures of Uygur adults with normal occlusion. At the same time, Bayers discriminant analysis was used to identify and evaluate the cluster results. RESULTS: Uygur adults with normal occlusion were divided into three patterns according to the multifactor cluster analytic results: horizontal tendency pattern (40%), medial pattern (43%) and vertical tendency pattern (17%). When the horizontal tendency pattern was compared with the medial pattern, it showed that the height of S-Go increased (P < 0.05), while the height of ANS-Xi-Pm decreased (P < 0.05); The proportion of S-Go/N-Me increased (P < 0.01). The angle of Ar-Go-Me and Y axis decreased (P < 0.05), which meant that the mandible rotated in the counter-clockwise direction. SN-MP, PP-MP, OP-MP, MP-FH all decreased (P < 0.01), which meant that the SN plane, the PP plane, the occlusion plane and the MP plane all had the trend of hypodivergence. When the vertical tendency pattern was compared with the medial pattern, the height of Ar-Fo decreased (P < 0.01), while the height of ANS-Me increased (P < 0.01); The angle of Ar-Go-Me, Y axis, SN-MP, PP-MP, OP-MP and MP-FH all increased (P < 0.01). These results showed that the mandible rotated in the clockwise direction and the SN plane, the PP plane, the occlusion plane, and the MP plane all had the trend of hyperdivergence. At last, according to the different skeletal patterns, the normal cephalometric values of Uygur adults with normal occlusion were established. CONCLUSION: Significantly craniofacial structure difference exist in the adults with normal occlusion. Therefore, it is necessary to establish the normal cephalometric values of Uygur adults with normal occlusion according to different skeletal patterns.

Adolescent↗
PubMed2000

[Study on IGF-I regulation the proliferation of rat condylar chondrocytes in vitro].

This study was aimed at the mechanism for the changes in the proliferation of cultured rat mandibular condylar chondrocytes. Flow cytometry was used to explore the changes of cellular DNA content and cell cycles of passaged condylar chondrocytes. The results showed that when the mandibular condylar chondrocytes were cultured with IGF-I for 24 hours and 96 hours, the cellular proliferation in the experimental group enhanced higher than that in the control group. It was implied that IGF-I may be a mitogen on rat mandibular condylar chondrocytes. The mitogenic effect of IGF-I had a lag period.

Animals↗
PubMed2000

[The establishment of a computerized growth prediction system].

Natural craniofacial growth plays an important role in the etiology of malocclusion. So, craniofacial growth prediction is very necessary in orthodontics. The present author have developed a new-typed computerized craniofacial growth predition system, which was designed in the general sense of craniofacial growth. According to a unique method, the system could automatically predict of craniofacial growth to different craniofacial growth pattern. It can be used as an auxilliary tool in clinical, teaching and researches in orthodontics.

Adolescent↗
PubMed1999

Single-residue alteration in alpha-conotoxin PnIA switches its nAChR subtype selectivity.

alpha-Conotoxins are disulfide-rich peptides that are competitive antagonists of nicotinic acetylcholine receptors (nAChRs). Despite their small size, different alpha-conotoxins are able to discriminate among different subtypes of mammalian nAChRs. In this report, the activity of two peptides from the venom of Conus pennaceus, alpha-conotoxins PnIA and PnIB, are examined. Although the toxins differ in only two residues, PnIA preferentially blocks alpha3beta2 nAChRs, whereas PnIB prefers the alpha7 subtype. Point mutation chimeras of these alpha-conotoxins were synthesized and their activities assessed on Xenopus oocytes expressing specific nAChRs. Change of a single residue, Ala10 to Leu, in PnIA (to form PnIA [A10L]) converts the parent peptide from alpha3beta2-preferring to alpha7-preferring; furthermore, PnIA [A10L] blocks the alpha7 receptor with an IC(50) (12.6 nM) that is lower than that of either parent peptide. Kinetic analysis indicates that differences in affinity among the analogues are primarily due to differences in off-rate, with PnIA [A10L]'s interaction with alpha7 having the smallest off-rate (k(off) = 0.17 min(-)(1)). Thermodynamic analysis indicates that Leu10 enhances the peptide's interaction with alpha7, but not alpha3beta2, receptors, whereas Ser11 (in PnIA [N11S]) reduces its affinity for both alpha7 and alpha3beta2 nAChRs.

Amino Acid Sequence↗
PubMed1999

A plant-like vacuolar H(+)-pyrophosphatase in Plasmodium falciparum.

Inorganic pyrophosphate promoted the acidification of a subcellular compartment in cell homogenates of Plasmodium falciparum trophozoites. The proton gradient driven by pyrophosphate was collapsed by addition of NH(4)Cl or the K(+)/H(+) exchanger nigericin and eliminated by the pyrophosphate analog aminomethylenediphosphonate. Pyrophosphatase activity was dependent upon K(+), and partially inhibited by Na(+). The presence of a plant-like vacuolar H(+)-translocating pyrophosphatase (V-H(+)-PPase) was confirmed using antibodies raised against conserved peptide sequences of the enzyme, which cross reacted with a protein band of 76.5 kDa. Immunofluorescence microscopy using these antibodies showed a general fluorescence over the whole parasites and intracellular bright spots suggesting a vesicular and plasma membrane localization. Together, these results indicate the presence in P. falciparum of a V-H(+)-PPase of similar characteristics to those of the enzyme from plants.

Animals↗
PubMed1999

Suprachiasmatic nuclei monoamine metabolism of glucose tolerant versus intolerant hamsters.

A critical role for temporal organization of dopaminergic and serotonergic activities within the suprachiasmatic nuclei (SCN) in the regulation of peripheral glucose metabolism has been postulated. This study employed in vivo microdialysis to investigate the temporal extracellular profiles of dopamine and serotonin metabolites in the SCN of freely behaving naturally glucose tolerant and intolerant Syrian hamsters. Microdialysis samples from the right SCN of awake, glucose tolerant or intolerant hamsters held on 14 h daily photoperiods were collected every 2 h over a 24 h period and assayed via HPLC for the metabolites of dopamine: homovanillic acid (HVA) and serotonin (5-hydroxyindolacetic acid, 5-HIAA). Among glucose tolerant hamsters, daily rhythms of SCN HVA and 5-HIAA were observed with coincident plateaus throughout the nocturnal phase of the day (both p<0.01). Relative to glucose tolerant hamsters, glucose intolerant animals exhibited a loss in the daily rhythm of SCN HVA (p<0.0001) and 5-HIAA (p<0.02) due to marked reductions (70%) throughout the 24 h period in HVA levels and comparative decreases (35%) in nocturnal peak levels of 5-HIAA. These findings demonstrate that daily profiles of extracellular dopamine and serotonin activities in the SCN, known to influence glucose metabolism, differ between glucose tolerant and intolerant hamsters.

Analysis of Variance↗
PubMed1999

Anterolateral thigh flap: A review of 168 cases.

The anterolateral thigh flap based on the descending branch of the lateral circumflex femoral vessel is one of the musculocutaneous or septocutaneous flaps in the thigh. The descending branch of the lateral circumflex femoral vessel has either perforating branches or direct cutaneous branches from the intermuscular space to the anterolateral femoral skin. Since 1983, we have transferred 168 anterolateral thigh flaps for reconstruction of old burn scars, infected wounds, carcinoma excisions, for coverage of open bone fracture of the lower leg, and for congenital diseases. One hundred fifty-two cases were free flaps. The other 16 cases were pedicled flaps. The skin branches were divided into four types in our clinical series: musculocutaneous perforators (135/168 [80.4%]); intermuscular cutaneous perforators (16/168 [9.5%]); direct cutaneous branches (14/168 [8.3%]); and tiny cutaneous perforators (3/168 [1.8%]). The results were satisfactory. Only one case resulted in a failure due to tiny cutaneous branches.

Adolescent↗
PubMed1999

Studies on in vitro metabolism of shikonin.

Shikonin is one of the active components isolated from the root of Arnebia euchrona (Royle) Johnst. It has been shown to possess significant antibacterial, antiinflammatory and antitumour activities and has been used clinically. In this paper, rat liver microsomes were incubated in vitro to study the metabolism of shikonin and a reverse-phase high performance liquid chromatography/photodiode array detector (DAD) method was used to separate and detect the metabolites. The effects of several factors on the metabolism were investigated and the metabolic system was optimized. The main metabolites were purified by RP-HPLC and their structures were determined by UV, 1H-NMR and MS. S-1 was dihydroxylated shikonin, S-2 was 2-OH shikonin and S-3 was 6-OH or 7-OH shikonin.

Animals↗
PubMed1999

Long-term infusion of norepinephrine plus serotonin into the ventromedial hypothalamus impairs pancreatic islet function.

To examine the possibility of a cause-effect relationship between enhanced monoamine content in the ventromedial hypothalamus ([VMH] a characteristic of hyperinsulinemic and insulin-resistant animals) and islet dysfunction, we infused norepinephrine ([NE] 25 nmol/h) and/or serotonin ([5-HT] 2.5 nmol/h) into the VMH of normal hamsters for 5 weeks and then examined insulin release from the isolated pancreatic islets. VMH infusion of NE + 5-HT, but not of either neurotransmitter alone, produced a marked leftward shift in the dose-response curve of glucose-induced insulin release (twofold to sixfold increase at 5 to 7.5 mmol/L glucose v vehicle-treated animals). In addition, the islet responsiveness to 1 micromol/L NE and 10 micromol/L acetylcholine was abolished in these NE + 5-HT VMH-infused hamsters. These findings indicate that an increase of NE and 5-HT content in the VMH can induce dysregulation of islet insulin release in response to glucose and neurotransmitters. Inasmuch as VMH NE and 5-HT levels are elevated in hyperinsulinemic and insulin-resistant animals, the present findings suggest that an endogenous increase in these hypothalamic monoamines may contribute to islet dysfunction, which is one of the characteristics of type 2 diabetes.

Acetylcholine↗
PubMed1999

Differences in soft tissue profile changes following mandibular setback in Chinese men and women.

PURPOSE: This study investigated the soft tissue profile changes after surgical correction of mandibular prognathism in Chinese patients and evaluated the sex differences in the ratios of soft tissue to hard tissue change. PATIENTS AND METHODS: Forty-three adult Chinese patients (18 men and 25 women) with mandibular prognathism were treated by intraoral oblique or vertical ramus osteotomy. Lateral cephalometric radiographs were taken presurgically and between 6 to 12 months postsurgically, and specific soft and hard tissue points were digitized and analyzed with a computer-aided system. RESULTS: As a result of surgical setback of the mandible, the soft tissue to hard tissue change ratios were: Li:Ii = 0.71:1, Si:B = 0.90:1, Pg':Pg = 0.94:1 for the males; and Li:Ii = 0.82:1, Si:B = 0.92:1, Pg':Pg = 1.06:1 for the females. CONCLUSION: The changes in soft tissue were closely correlated with the hard tissue movement after surgical setback of mandible. The average ratios of soft tissue to hard tissue change in horizontal direction appear to show a gender difference, which suggests the need for different ratios when predicting the results of orthognathic surgery.

Adult↗