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Biomedical subjects

H Shi

Publications and source records attributed to H Shi.

At least 127 records · Page 7Linked to original sources

Case-control study of the D2 dopamine receptor gene and smoking status in lung cancer patients.

BACKGROUND: Interindividual differences in the structure and expression of the dopamine receptor genes affect dopamine availability and may be the genetic basis for variation in vulnerability to tobacco smoking. In this study, prevalences of polymorphisms in the TaqIA allele (A1 and A2) and the TaqIB allele (B1 and B2) of the D2 dopamine receptor gene in 157 lung cancer case patients and 126 control subjects were determined to assess whether individuals homozygous or heterozygous for the less common A1 and B1 alleles are more vulnerable to nicotine addiction. METHODS: Case and control subjects were accrued from an ongoing epidemiologic study. Blood samples were collected from them and subjected to molecular genetic analyses. Subjects were interviewed to obtain relevant information. Current and former smokers were administered a questionnaire to quantify their addiction to nicotine. RESULTS: The combined B1B2 genotypes appeared to be more prevalent in ever smokers than in never smokers among case patients (30.3% versus 13.3%; two-sided P = .233) and among control subjects (30.9% and 0%; two-sided P = .02); statistically significant differences were not observed among those with A1 genotypes. Statistically significant correlations between the presence of the A1 and B1 alleles were observed (r = .73 for case subjects and r = .76 for control subjects; two-sided P<.001). Individuals with rarer genotypes reported having been substantially younger at the time of smoking initiation (statistically significant for both A1 and B1) and having attempted to quit smoking fewer times (statistically significant for only A1). CONCLUSION: Variant alleles of the D2 dopamine receptor gene may play a role in determining nicotine addiction, although the associations between the at-risk genotypes and measures of nicotine addiction were not entirely consistent.

Aged↗

Stoichiometric and kinetic studies on Ginkgo biloba extract and related antioxidants.

Owing to increasing evidence showing the importance of lipid peroxidation in oxidative stress in vivo, the role and evaluation of antioxidants have received much attention. Ginkgo biloba extract (GBE), well-known as an efficient drug against diseases induced by free radicals, has been suggested to exert its effect by antioxidant action. A method was established to determine the activity of GBE as a hydrogen donor by stoichiometric and kinetic studies, and GBE was compared with several other antioxidants such as alpha-tocopherol, propyl gallate, and two kinds of flavonoids which are found in GBE, quercetin, and kaempferol. It was found that there were 6.62 x 10(19) active hydrogens in 1 g of GBE. Stoichiometric studies showed that one molecule of alpha-tocopherol reacted with one molecule of galvinoxyl radical. For quercetin, kaempferol and propyl gallate, the experimental stoichiometric numbers were 4.0, 1.9, and 3.1, respectively. The rates of reaction of antioxidants with galvinoxyl in ethanol were determined spectrophotometrically, using a stopped-flow technique. The second-order rate constant, k2, obtained at 25 degrees C was 0.13 (g/L)(-1)s(-1) for GBE and 5.9 x 10(3), 2.1 x 10(3), 1.2 x 10(4), and 2.4 x 10(3) M(-1)s(-1) for quercetin, kaempferol, propyl gallate, and alpha-tocopherol, respectively. The second-order rate constant, k2', on the molar basis of active hydroxyl groups in the tested substances obtained at 25 degrees C decreased in the order of propyl gallate > alpha-tocopherol > quercetin > GBE approximately kaempferol. This is the first study on GBE as an antioxidant which reports both stoichiometric and kinetic results.

Antioxidants↗

The effect of multiple doses of ritonavir on the pharmacokinetics of rifabutin.

OBJECTIVE: To investigate the effects of ritonavir on the pharmacokinetics of rifabutin. METHODS: In a multiple-dose, randomized, parallel-group, double-blind study, subjects received 150 mg rifabutin daily for 24 days coadministered on days 15 to 24 with twice-daily doses of either placebo or ritonavir (300 mg on day 15, 400 mg on day 16, and 500 mg on days 17 to 24). Plasma concentrations of rifabutin and 25-O-desacetylrifabutin were measured by HPLC, and the pharmacokinetics were determined after the rifabutin doses on days 14 and 24. RESULTS: For subjects receiving rifabutin and placebo who completed the study (n = 11), there were small but statistically significant differences (< or = 32%) in several rifabutin and 25-O-desacetylrifabutin pharmacokinetic parameters between the regimens of rifabutin alone and rifabutin with placebo. In contrast, the effect of ritonavir on rifabutin pharmacokinetics of subjects completing the study (n = 5) was substantial. Rifabutin mean minimum observed concentration (Cmin), maximum observed concentration (Cmax), and area under the concentration-time curve [AUC(0-24)] increased by approximately sixfold, 2.5-fold, and fourfold, respectively, and 25-O-desacetylrifabutin mean Cmin, Cmax, and AUC(0-24) increased by approximately 200-, 16-, and 35-fold, respectively, when coadministered with ritonavir compared with rifabutin administered alone. The sum of the mean AUC(0-24) of rifabutin and 25-O-desacetylrifabutin increased nearly sevenfold when coadministered with ritonavir. CONCLUSIONS: Ritonavir inhibited the metabolism of rifabutin and 25-O-desacetylrifabutin, suggesting that both are metabolized at least in part by CYP3A. Ritonavir may have enhanced rifabutin bioavailability by reducing either intestinal of hepatic metabolism of both. Clarithromycin is an alternative to rifabutin for antimycobacterial therapy that may be administered concurrently with ritonavir. Administration of ritonavir with a reduced rifabutin dosage regimen (150 mg every Monday, Wednesday, and Friday) is being investigated.

Adult↗

Kinetics of biodegradation of di-n-butyl phthalate in continuous culture system.

The characteristics of microbial growth and kinetics of DBP biodegradation was studied in a continuous culture system using DBP as a sole source of carbon. The results showed that, at high substrate concentration, the microbial growth was inhibited by DBP, and can be described by the Haldane model. Kinetic parameters based on Haldane substrate inhibition were evaluated. The values were mu(m) = 0.38 h-1, Ki = 86 mg/l, Ks = 28 mg/l. The DBP concentration to avoid substrate inhibition was inferred theoretically and determined to be 49 mg/L.

Biodegradation, Environmental↗

Recursive partitioning for the identification of disease risk subgroups: a case-control study of subarachnoid hemorrhage.

Recursive partitioning is a nonparametric technique that produces a classification tree in which subjects are assigned to mutually exclusive subsets according to a set of predictor variables. We examined the utility of recursive partitioning as a supplement to logistic regression for the multivariable analysis of data from case-control studies, demonstrating the technique using data from women enrolled in a population-based study of subarachnoid hemorrhage. The classification tree produced by recursive partitioning consisted of three main risk subgroups: (1) elderly women who had long-standing hypertension and who were not smokers, (2) middle-aged women who were cigarette smokers and frequent binge drinkers, and (3) women in whom risk variables indicate relative estrogen deficiency (i.e., postmenopausal status, no recent exposure to hormone replacement therapy, cigarette smoking). As a supplemental method, recursive partitioning not only identifies subgroups with varying risks, but also may uncover interactions between variables that may be overlooked in the traditional application of logistic regression to case-control data.

Aged↗

Strategies for protein-based nanofabrication: Ni2+-NTA as a chemical mask to control biologically imposed symmetry.

BACKGROUND: Technologies that improve control of protein orientation on surfaces or in solution, through designed molecular recognition, will expand the range of proteins that are useful for biosensors, molecular devices and biomaterials. A limitation of some proteins is their biologically imposed symmetry, which results in indistinguishable recognition surfaces. Here, we have explored methods for modifying the symmetry of an oligomeric protein that exhibits useful self-assembly properties. RESULTS: Escherichia coli glutamine synthetase (GS) contains 24 solvent-exposed histidines on two symmetry-related surfaces. These histidines drive a metal-dependent self-assembly of GS tubes. Immobilization of GS on the affinity resin Ni2+-NTA followed by on-column modification with diethyl pyrocarbonate affords asymmetrically modified GS that self-assembles only to the extent of 'short' dimeric GS tubes, as demonstrated by electron microscopy, dynamic light scattering and atomic force microscopy. The utility of Ni2+-NTA as a chemical mask was also demonstrated for asymmetric modification of engineered cysteines adjacent to the natural histidines. CONCLUSIONS: Current genetic methods do not provide distinguishable recognition elements on symmetry-related surfaces of biologically assembled proteins. Ni2+-NTA serves as a mask to control chemical modification in vitro of residues within symmetry-related pairs, on proteins containing functional His-tags. This strategy may be extended to modification of a wide range of amino acids with a myriad of reagents.

Biocompatible Materials↗

The lesions of the pterygopalatine and infratemporal spaces: Computed tomography evaluation.

OBJECTIVE: The purpose of this study was to categorize the computed tomography features of lesions affecting the pterygopalatine fossa and infratemporal fossa and thus aid in the diagnosis of these lesions. DESIGN: Eighty-six patients with lesions of the pterygopalatine fossa and infratemporal fossa were examined with computed tomography; the lesions were confirmed by both surgery and biopsy. The patients were divided into three groups: group I consisted of patients in whom the lesions had originated in one or both fossae; group II, of patients in whom the lesions originated in other oral and maxillofacial regions but showed extension into the pterygopalatine and infratemporal fossae; and group III, of patients in whom the lesions had multicentric origins. RESULTS: Of the 11 cases in group I, demarcation was confined to both fossae in 4 patients, and involvement of the adjacent structures was shown on computed tomography images in 7 patients. Involved structures included the maxillary sinus (4 sides), nasal cavity (3 sides), mandibular ramus (6 sides), buccal space (2 sides), base of the skull (5 sides), palate (3 sides), and parapharyngeal space (5 sides). In the 70 cases in group II, computed tomography images showed that lesions had invaded both fossae via following routes: (1) 40 lesions in the maxillary sinus had infiltrated posterolaterally into 26 pterygopalatine and 39 infratemporal fossae; (2) two nasal cavity and three nasopharynx tumors had infiltrated laterally or lateroanteriorly into five pterygopalatine and one infratemporal fossae; (3) lesions originating in mandibular rami (9 lesions), buccal regions (4 lesions), parapharyngeal spaces (1 lesion) and parotid glands (1 lesion) had intruded medially into 15 infratemporal fossae; (4) two temporal bone tumors had encroached inferiorly on two infratemporal fossae; (5) four palate tumors had led to involvement of three pterygopalatine and four infratemporal fossae; and (6) four inflammatory diseases of the facial spaces involved two pterygopalatine and four infratemporal fossae. Group III lesions (5 cases) affecting one pterygopalatine and five infratemporal fossae were hemangiomas; one was a malignant lymphoma. CONCLUSION: Group I lesions may involve the adjacent anatomic structures of both pterygopalatine and infratemporal fossae in every direction. Group II lesions that correspond to the various origins of the maxillofacial region have different pathways of infiltration into the pterygopalatine or infratemporal fossae. Computed tomography examination is very important in the evaluation of lesions involving the pterygopalatine and infratemporal fossae.

Adolescent↗

Binding of the 60-kDa Ro autoantigen to Y RNAs: evidence for recognition in the major groove of a conserved helix.

The 60-kDa Ro autoantigen is normally complexed with small cytoplasmic RNAs known as Y RNAs. In Xenopus oocytes, the Ro protein is also complexed with a large class of variant 5S rRNA precursors that are folded incorrectly. Using purified baculovirus-expressed protein, we show that the 60-kDa Ro protein binds directly to both Y RNAs and misfolded 5S rRNA precursors. To understand how the protein recognizes these two distinct classes of RNAs, we investigated the features of Y RNA sequence and structure that are necessary for protein recognition. We identified a truncated Y RNA that is stably bound by the 60-kDa Ro protein. Within this 39-nt RNA is a conserved helix that is proposed to be the binding site for the Ro protein. Mutagenesis of this minimal Y RNA revealed that binding by the 60-kDa Ro protein requires specific base pairs within the conserved helix, a singly bulged nucleotide that disrupts the helix, and a three-nucleotide bulge on the opposing strand. Chemical probing experiments using diethyl pyrocarbonate demonstrated that, in the presence of the two bulges, the major groove of the conserved helix is accessible to protein side chains. These data are consistent with a model in which the Ro protein recognizes specific base pairs in the conserved helix by binding in the major groove of the RNA. Furthermore, experiments in which dimethyl sulfate was used to probe a naked and protein-bound Y RNA revealed that a structural alteration occurs in the RNA upon Ro protein binding.

Animals↗

Dose-response relationship of lansoprazole to gastric acid antisecretory effects.

BACKGROUND: Proton pump inhibitors have been found to be effective in numerous studies in patients with peptic ulcer disease, particularly associated with Helicobacter pylori and gastro-oesophogeal reflux disorders. Optimal healing rates of antisecretory therapy for peptic acid disease is dependent upon the degree and duration of acid suppression and the length of treatment. OBJECTIVE: To evaluate the extent and duration of gastric acid suppression of several lansoprazole regimens, administered for 5 consecutive days in 32 healthy adult male subjects. METHODS: Intragastric 24-h pH monitoring was performed in 32 healthy subjects in a randomized, double-blind, four-way crossover study. Sixteen subjects (Group 1) received lansoprazole 30 mg o.d. (once daily), 15 mg b.d. (twice daily), 30 mg b.d. and 30 mg t.d.s. (three times a day) for 5 days; and 16 subjects (Group 2) received lansoprazole 30 mg o.d., 60 mg o.d., 60 mg b.d. and 60 mg t.d.s. for 5 days. RESULTS: Mean 24-h intragastric pH values for lansoprazole 30 mg o.d., 15 mg b.d., 30 mg b.d. and 30 mg t.d.s. were 4.47, 4.57, 5.07 and 5.63, respectively. Multiple-dose regimens of lansoprazole 30 mg b.d. and t.d.s. produced greater acid suppression compared to lansoprazole 30 mg o.d. and 15 mg b.d. There was no significant difference in acid suppression between lansoprazole 30 mg o.d. and 15 mg b.d. Mean 24-h intragastric pH values for lansoprazole 30 mg o.d., 60 mg o.d., 60 mg b.d. and 60 mg t.d.s. were 4.13, 4.45, 5.19 and 5.13, respectively. Multiple-dose regimens of lansoprazole 60 mg b.d. and t.d.s. produced significantly greater acid suppression compared to lansoprazole 30 mg o.d. and 60 mg o.d. There was no significant difference in acid suppression between lansoprazole 30 mg o.d. and 60 mg o.d. Lansoprazole 30 mg t.d.s., 60 mg b.d. and 60 mg t.d.s. produced significantly greater percentage time above pH 3, 4, 5 and 6 than did lansoprazole 30 mg o.d. Post-regimen serum gastrin values increased by 50-130% from pre-study mean values but remained within normal range and returned to pre-study values 7-14 days post-dosing. CONCLUSIONS: Multiple-dose regimens of lansoprazole (> or =30 mg b.d. for 5 days) produce significantly increased intragastric pH and significantly longer duration of increased intragastric pH than does lansoprazole 30 mg administered once daily.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Structure-activity relation of N-alkyl tetracaine derivatives as neurolytic agents for sciatic nerve lesions.

BACKGROUND: N-butyl tetracaine has local anesthetic and neurolytic properties. An injection of this drug at the rat sciatic notch produces rapid onset and nerve impairment lasting > 1 week. This study aimed to elucidate the structure-activity relation of various tetracaine derivatives to design better neurolytic agents. METHODS: N-alkyl tetracaine salts (n = 2-6) were synthesized, and their ability to elicit sciatic nerve impairment of sensory and motor functions in vivo was tested in rats. A single dose (0.1 ml at 37 mM) was administered close to the sciatic nerve at the sciatic notch. Regeneration was assessed morphologically in transverse sections of treated nerves. Finally, the drug potency in blocking Na+ currents was studied under voltage-clamp conditions. RESULTS: N-ethyl and N-propyl tetracaine derivatives were non-neurolytic and elicited complete sciatic nerve block lasting 3-7 h. In contrast, N-butyl, N-pentyl, and N-hexyl tetracaine derivatives were strong neurolytic agents and elicited functional impairment of sciatic nerve for > 1 week. All derivatives were strong Na+ channel blockers, more potent than tetracaine if applied intracellularly. External drug application showed marked differences in their wash-in rate: tetracaine > N-hexyl > N-butyl > N-ethyl tetracaine. All derivatives were trapped within the cytoplasm and showed little washout within 7 min. CONCLUSIONS: When n-alkylation is 4-6, n-alkyl tetracaine appeared as a strong neurolytic agent. Neurolytic derivatives retained their local anesthetic activity and elicited rapid onset of nerve block after injection. Such derivatives are potential local anesthetic-neurolytic dual agents for chemical lesions of the sciatic nerve.

Anesthetics, Local↗

Prediction of postoperative knee flexion in Insall-Burstein II total knee arthroplasty.

Postoperative knee flexion in patients undergoing Insall-Burstein-II total knee arthroplasty at 2 years was evaluated regarding two basic questions: what groups of patients gain or lose the most flexion and what groups of patients have the best or worst postoperative flexion. Thirteen preoperative variables (maximum flexion, flexion arc, tibiofemoral angle, quadriceps strength, extensor lag, Knee Society score, Knee Society patient assessment, gender, age, height, weight, diagnosis, and surgeon) and four postoperative variable (leg length change, tibiofemoral angle, distance from patella to the joint line, and the tibial prosthesis anteroposterior translation on a lateral radiograph) were used in an attempt to explain postoperative flexion. The analysis was performed on 164 consecutive Insall-Burstein-II total knees in which the data were gathered prospectively on a time oriented medical record database. A regression tree analysis was used to identify several groups of patients, characterized by preoperative factor values, who had markedly above average performance on postoperative flexion. The preoperative factors identified include preoperative flexion, flexion arc, tibiofemoral angle, extensor lag, diagnosis, and age. The only postoperative variable of significance was tibiofemoral angle. Among the potential determinants of postoperative flexion that failed to appear predictive were the Knee Society scores and surgeon. Preoperative flexion is known to be a critical determinant of postoperative flexion in total knee replacement. However, in the current study, preoperative flexion accounted for only half of the difference between the best (122 degrees) and the worst (88 degrees) group, as determined with regression tree analysis.

Aged↗

Steady-state pharmacokinetics and electrocardiographic pharmacodynamics of clarithromycin and loratadine after individual or concomitant administration.

To evaluate the potential for an interaction between clarithromycin and loratadine, healthy male volunteers (n = 24) received each of the following regimens according to a randomized crossover design: 500 mg of clarithromycin orally every 12 h (q12h) for 10 days, 10 mg of loratadine orally q24h for 10 days, and the combination of clarithromycin and loratadine. A washout interval of 14 days separated regimens. The addition of loratadine did not statistically significantly affect the steady-state pharmacokinetics of clarithromycin or its active metabolite, 14(R)-hydroxy-clarithromycin. However, the addition of clarithromycin statistically significantly altered the steady-state maximum observed plasma concentration and the area under the plasma concentration-time curve over a dosing interval for loratadine (+36 and +76%, respectively) and for descarboethoxyloratadine (DCL), the active metabolite of loratadine (+69 and +49%, respectively). Clarithromycin probably inhibits the oxidative metabolism of loratadine and DCL by the cytochrome P-450 3A subfamily. Electrocardiograms (n = 12) were obtained over 24-h periods at baseline and steady state (day 10). The mean maximum QTc interval and area under the QTc interval-time curve on day 10 were modestly increased (<3%) from baseline for all three regimens, but no QTc interval exceeded 439 ms for any subject. Elevated steady-state concentrations of loratadine and DCL do not appear to be associated with adverse cardiovascular effects related to prolongation of the QTc interval. Loratadine and clarithromycin were well tolerated, alone and in combination.

Adolescent↗

[Mutation of breast cancer susceptibility gene in ovarian cancer and its clinical significance].

OBJECTIVE: To detect breast cancer susceptibility gene (BRCA1) mutation in ovarian cancer and to look for correlations between BRCA1 mutation and hereditary ovarian cancer. METHODS: Mutation of BRCA1 gene in 4 patients with hereditary ovarian cancer and 31 patients with sporadic ovarian cancer were screened by polymerase chain reaction-single strand conformation polymorphism analysis with non-isotopic silver staining method. RESULTS: 2 mutations of BRCA1 gene were found in 2 of 3 patients belonged to hereditary breast-ovarian cancer syndrom (HBOC) which were located in exon 2 and 21 respectively. No mutation was found in 31 cases of sporadic ovarian cancer and 1 case of hereditary site-specific ovarian cancer. CONCLUSION: BRCA1 mutation was probably closely related to hereditary breast-ovarian cancer syndrome. Detection of BRCA1 gene mutation was helpful to diagnose HBOC families.

Aged↗

[Production of purified Japanese encephalitis vaccine from Vero cells with roller bottles].

OBJECTIVE: To study the production process of purified Japanese encephalitis (JE) vaccine from Vero cells cultivated in roller bottles to improve the quality of JE vaccine. METHODS: The 15 L roller bottles were used for propagation of Vero cells and JE virus, then the virus was inactivated, concentrated, treated by protamine sulphate, purified by sucrose gradient density centrifugation and lyophylized as final product. RESULTS: Three batches of high quality lyophylized vaccine were produced and the quality control tests of vaccine for human use had been passed. CONCLUSION: Using roller bottles to cultivate continuous cell line-Vero cells for JE vaccine production is feasible.

Animals↗

Lipoprotein (a) concentration and apolipoprotein (a) phenotype in subjects with type 2 diabetes mellitus.

OBJECTIVE: To investigate the apolipoprotein (a) [apo(a)] polymorphism in the patients with type 2 diabetes mellitus and its relationship with complications. METHODS: In this study, we tested apo(a) phenotype via modified Utermann and Guo method in the 40 non-diabetic controls and 176 subjects with type 2 diabetes and analyzed the relationship between apo(a) phenotypes and micro- and macrovascular complications, including nephropathy, neuropathy, retinopathy, hypertension, coronary heart disease and cerebral infarction. RESULTS: Among the 40 non-diabetic controls, the frequencies of S3S2, S4 and S4S2 were 20%, 70% and 10% respectively and the serum lipoprotein (a) [Lp(a)] level was 0.08 +/- 0.07 mg/L. While the frequencies of S2, S3, S3S2, S4, S4S2, S4S3 were 18.18%, 20.45%, 17.05%, 34.09%, 4.55% and 5.68% in the diabetics and the Lp(a) concentration was 0.13 +/- 0.11 mg/L, with significant difference between the diabetics and non-diabetic controls. In comparison with the diabetics without complications, the frequency of apo(a) phenotype significantly differed in patients with nephropathy, nephropathy, hypertension, coronary heart disease and cerebral infarction except for diabetic retinopathy. In comparison with patients with S2 phenotype, the levels of fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG) and glycated hemoglobin A1c (HbA1c) were lower in patients with S4 phenotype. The concentration of Lp(a) and urine albumin index (Alb/Cr) were significantly different among diabetics with different apo(a) phenotype, the highest being in patients with S2, secondly S3, and the lowest S4. CONCLUSION: There were significant differences in the frequency of apo(a) phenotype between subjects with type 2 diabetes and non-diabetic controls, and also in diabetics with or without microvascular and macrovascular diseases. The underlying linkage might be microalbuminuria and insulin resistance.

Adult↗

[Morphologic discrepancies of coronary atherosclerotic lesions between patients with stable and unstable angina plus acute myocardial infarction].

OBJECTIVE: To compare the morphological difference of coronary atherosclerotic plaques in patients with stable angina(SA), unstable angina (UA) and acute myocardial infarction (AMI). METHODS: 101 autopsy cases of patients with SA, UA and/or AMI were studied using routine histological and immunohistochemical staining. RESULTS: Coronary atherosclerotic plaques in SA patients were mainly the fibrous plaques with no or just very small necrotic cores; rich in smooth muscle cells and collagen fibers, less foamy cells (stable plaque), low incidence of plaque rupture (14% only) and no thrombosis found. The atherosclerotic plaques in UA and AMI patients were mainly the atheroma (unstable plaque) with large necrotic core (> 40%), thin fibrous cap, less smooth muscle cells and abundant foamy cells. The incidences of plaque rupture were 76% and 82%, thrombosis 81% and 91% respectively in 58 cases of UA and 22 cases of AMI, and the incidence of UA is statistically significant in comparing with that of the SA group (P < 0.001). CONCLUSION: In SA group, stable plaque was the main finding, plaque rupture and thrombosis rare. While in UA and AMI patients, unstable plaques predominant with a high incidence of plaque rupture and thrombosis which were the leading cause of acute coronary events.

Angina Pectoris↗

[Expression of thrombopoietin related genes in patients with idiopathic thrombocytopenic purpura].

OBJECTIVE: To explore the expression of thrombopoietin (Tpo) and its receptor c-mpl in bone marrow from patients with idiopathic thrombocytopenic purpura(ITP). METHODS: Non-radioactive in situ hybridization was used to detect tpo, c-mpl mRNA. Immune cytochemistry was used to detect MPL on megakaryocyte. RESULTS: The expression of tpo, c-mpl mRNA in bone marrow and MPL on megakaryocyte in patients with ITP was increased. CONCLUSION: c-mpl mRNA was regulated at transcriptional level. A negative feedback loop was involved in the regulation of megakaryopoiesis in bone marrow. MPL may be involved in the regulation of circulating Tpo.

Bone Marrow Cells↗