Broadband external cavity tunable quantum dot lasers with low injection current density

Broadband grating-coupled external cavity laser, based on InAs/GaAs quantum dots, is achieved. The device has a wavelength tuning range from 1141.6 nm to 1251.7 nm under a low continuous-wave injection current density (458 A/cm(2)). The tunable bandwidth covers consecutively the light emissions from both the ground state and the 1st excited state of quantum dots. The effects of cavity length and antireflection facet coating on device performance are studied. It is shown that antireflection facet coating expands the tuning bandwidth up to ~150 nm, accompanied by an evident increase in threshold current density, which is attributed to the reduced interaction between the light field and the quantum dots in the active region of the device.

A clinical study of 115 patients with extranodal natural killer/T-cell lymphoma, nasal type

AIMS

To investigate the clinicopathological features, treatment outcomes, and prognostic factors in patients with extranodal natural killer (NK)/T-cell lymphoma, nasal type.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 115 patients diagnosed with extranodal NK/T-cell lymphoma, nasal type who were admitted to our hospital between January 1991 and June 2006.

RESULTS

In total, 107 patients were available for follow-up. After the completion of treatment, 48 patients (44.9%) achieved a complete remission. By the end of the follow-up period, 60 patients (56.1%) had died from local recurrence or metastases. The mean survival duration was 70.0 months, the median survival duration was 42 months, and the 5-year survival rate was 39.4%. The mean survival durations of the three treatment groups of chemoradiotherapy, radiotherapy and palliative treatment were 91.6, 60.1 and 17.6 months, respectively. The median survival durations were 72.0, 42.0 and 10 months, respectively. Patients treated with > 50 Gy had better local control and survival than the < 50 Gy group. However, there was no significant difference between patients having fewer than four cycles of chemotherapy and patients having more than four cycles. Multifactor Cox regression model analysis showed that B symptoms, gender, International Prognostic Index (IPI) score, disease stage and therapy were all independent prognostic factors.

CONCLUSIONS

The prognosis of extranodal NK/T-cell lymphoma, nasal type is poor and significantly influenced by B symptoms, gender, IPI score, clinical staging and the method of treatment. Chemoradiotherapy should be the first choice for treatment.

Prolonged cardiac allograft survival in presensitized rats after a high activity Yunnan-cobra venom factor therapy

Complement-dependent antibody-mediated acute humoral rejection is the major obstacle of clinical transplantation across ABO incompatibility and human leukocyte antigen presensitization. We previously demonstrated that Yunnan-cobra venom factor (Y-CVF) could almost completely abrogate complement activity and successfully prevent hyperacute rejection in some xenotransplant models without any obvious toxicity. In this study we investigated whether depletion of complement by Y-CVF prevented acute humoral allograft rejection in presensitized rats thereby prolonging graft survival.

METHODS

Presensitization was achieved in Lewis rats by sequential grafting of three full-thickness skin pieces from Brown Norway rats. Serum cytotoxic alloantibody titers were determined by a modified in vitro complement-dependent microcytotoxicity assay. After presensitization, each Lewis rat received a heterotopic Brown Norway cardiac allograft. Fifteen recipients were divided into two groups: (1) no treatment control (n = 7); (2) Y-CVF therapy group (86 u/kg, IV, day -1) (n = 8). After cessation of the heart beat, allograft rejection was confirmed by pathologic as well as IgG and C3 immunohistochemical examinations.

RESULTS

The mean graft survival time was significantly prolonged to 99.50 +/- 38.72 hours among rats that received Y-CVF vs 12.71 +/- 13.94 hours in nontreated controls (P < .001). Upon pathological and immunohistochemical examination, acute humoral rejection was mainly exhibited in the control group, whereas acute cellular rejection was mainly displayed in the Y-CVF therapy group.

CONCLUSIONS

Our study demonstrated that complement depletion by Y-CVF significantly inhibited acute humoral allograft rejection in presensitized rats. As a therapeutic immunointervention tool for complement, Y-CVF has shown potential efficacy across ABO incompatible and positive cross-match barriers.

Factors influencing arsenic accumulation by Pteris vittata: a comparative field study at two sites

This study compared the factors influencing arsenic (As) accumulation by Pteris vittata at two sites, one containing As along with Au mineralization and the other containing Hg/Tl mineralization. The soils above these two sites contained high As concentrations (26.8-2955 mg kg(-1)). Although the As concentration, pH, soil cation exchange capacity and plant biomass differed significantly between the two sites, no differences were observed in the As concentrations in the fronds and roots, or the translocation factors, of P. vittata, suggesting that this species has consistent As hyperaccumulation properties in the field. The As concentration in the fronds was positively related to phosphorus (P) and potassium (K), but negatively related to calcium (Ca), at one site. This suggested that P, K and Ca influenced As accumulation by P. vittata in the field.

Vascular endothelial growth factor and its receptor Flk-1 are expressed in the hippocampus following entorhinal deafferentation

Vascular endothelial growth factor (VEGF) has been thought of as a mitogen that promotes proliferation of endothelial cells and as a neurotrophic factor that stimulates neurogenesis and axonal growth in both peripheral and central nervous systems. To investigate the potential involvement of VEGF in the lesion-induced reorganization in the brain, the expression changes of VEGF and its receptor Flk-1 were analyzed in the mouse hippocampus after transections of the entorhinal afferents. In situ hybridization and immunohistochemistry showed the time-dependent expression upregulation of VEGF mRNA and protein in the entorhinally denervated hippocampal stratum lacunosum-moleculare and dentate outer molecular layer, which initiated by 3 days postlesion, reached its maximum at 7-15 days postlesion, still persisted by 30 days postlesion for protein, and recovered to the normal levels at 30 days postlesion for mRNA and at 60 days postlesion for protein. Double labeling of VEGF and glial fibrillary acidic protein revealed that VEGF-expressing cells in the denervated areas were reactive astrocytes. Semi-quantitative RT-PCR analysis showed that VEGF receptor Flk-1 mRNA was also time-dependently upregulated in the deafferented hippocampus with its maximal elevation at 7-15 days postlesion while the Flt-1 mRNA levels remained unchanged at any time point we examined. Immunohistochemistry analysis also displayed the upregulation of Flk-1 protein in the denervated stratum lacunosum-moleculare and outer molecular layer with a time course similar to that of VEGF mRNA upregulation. Flk-1 receptors were found to be expressed not only by reactive astrocytes but also by neurites, which most likely belong to sprouting axons by 7 days postlesion and regrowing dendrites by 15-30 days postlesion. From these data we suggest that the spatiotemporal upregulation of VEGF and Flk-1 in the hippocampus is induced by entorhinal deafferentation and that VEGF may be involved in the structural reorganization in the deafferented hippocampus via directly or indirectly promoting neurite growth.

In vitro activities of small peptides from snake venom against clinical isolates of drug-resistant Mycobacterium tuberculosis

The recent re-emergence of tuberculosis, especially the multidrug-resistant cases, has highlighted the importance of screening effective novel drugs against Mycobacterium tuberculosis. In this study, the in vitro activities of small peptides isolated from snake venom were investigated against multidrug-resistant M. tuberculosis. Minimum inhibitory concentrations (MICs) were determined by the Bactec TB-460 radiometric method. A small peptide with the amino acid sequence ECYRKSDIVTCEPWQKFCYREVTFFPNHPVYLSGCASECTETNSKWCCTTDKCNRARGG (designated as vgf-1) from Naja atra (isolated from Yunnan province of China) venom had in vitro activity against clinically isolated multidrug-resistant strains of M. tuberculosis. The MIC was 8.5 mg/l. The antimycobacterial domain of this 60aa peptide is under investigation.

Role of CT in left-sided acute appendicitis: case report

We present the computed tomographic findings in a case of left-sided acute appendicitis associated with midgut malrotation, which is a rare anomaly. The inflamed appendix was visualized as a tubular, fluid-filled, enhancing structure in the left lower quadrant. The entire colon was located in the left abdomen. The presence of a superior mesenteric vein rotation sign ascertained the presence of midgut malrotation. Computed tomography is useful not only in providing accurate diagnosis of left-sided appendicitis but also in detecting associated rotational anomalies, which may require separate surgical correction.

Homocyclotirucallane and two dihydrophenanthrenes from Spiranthes sinensis

A novel homocyclotirucallane, sinetirucallol (1), and two additional new dihydrophenanthrenes, sinensols G (2) and H (3), were isolated from the aerial parts of Spiranthes sinensis (Pers.) Ames. Their structures were determined by various spectral analyses, including MS and two-dimentional nuclear magnetic resonance techniques. The structure of compound 1 was further confirmed by single-crystal X-ray analysis. The absolute configuration of 1 was determined by modified Mosher's method.

Purification and characterization of jerdofibrase, a serine protease from the venom of Trimeresurus jerdonii snake

A fibrin(ogen)olytic serine protease from Trimeresurus jerdonii venom was identified and purified to SDS-polyacrylamide gel electrophoresis homogeneity. It is a single chain polypeptide with a molecular weight of 32kDa under reduced condition and 28kDa under non-reduced condition, respectively. The venom protease catalysed the hydrolysis of some chromogenic substrates such as S2238, S2160, S2302 and S2251. It degraded Bbeta-chain of human fibrinogen preferentially. Also the enzyme degraded fibrin directly. Its enzymatic activity was completely inhibited by phenylmethylsulfonyl fluoride (PMSF), but not affected by EDTA. That suggested it was a serine protease. N-terminal sequence of the purified component showed high homology with other snake venom serine proteases.

Detection of Epstein-Barr virus DNA in the peripheral-blood cells of patients with nasopharyngeal carcinoma: relationship to distant metastasis and survival

PURPOSE

Nasopharyngeal carcinoma (NPC) has been proved to be an Epstein-Barr virus (EBV)-associated cancer. By use of nested polymerase chain reactions (PCRs), we examined whether the presence of EBV DNA in the peripheral-blood cells (PBC) can serve as a prognostic indicator for NPC.

PATIENTS AND METHODS

Peripheral blood from 124 patients with NPC who had no evidence of distant metastasis and 114 healthy volunteers with serologically positive findings for EBV infection was collected prospectively. Plasma and erythrocytes were separated. DNA was extracted from PBCs and analyzed by a nested PCR using primers specific to Epstein-Barr virus nuclear antigen 1 (EBNA-1). All patients were treated by radiotherapy with or without chemotherapy. Clinical parameters and status of EBNA-1 in PBCs were used for survival analysis using the Kaplan-Meier method and the Cox proportional hazards model.

RESULTS

Positive rates of EBNA-1 DNA in PBCs of NPC patients and healthy volunteers are 71% and 14%, respectively (P =.001). No significant difference was observed with regard to the clinical characteristics of patients who were EBNA-1-positive (n = 88) and those who were EBNA-1-negative (n = 36). After a median follow-up period of 38 months (range, 24 to 56 months), 29 of 88 EBNA-1-positive patients and only one of 36 EBNA-1-negative patients developed distant metastases (P =.00015). Kaplan-Meier estimates of overall survival (P =.0010), metastasis-free survival (P =.0004), and progression-free survival (P =.0004) were significantly lower for the patients in the EBNA-1-positive group than for those in the EBNA-1-negative group. Multivariate Cox analysis confirmed the same results.

CONCLUSION

The presence of EBNA-1 DNA in PBCs is a novel, important risk factor for patients with NPC that indicates a significantly higher risk of developing distant metastasis as well as a lower survival rate.

Diffuse panbronchiolitis--a case report

Diffuse panbronchiolitis (DPB) is a chronic progressive obstructive disease of the airways. Of unknown aetiology, it is responsive to macrolide therapy. Although not uncommon among the Japanese, it is rare in other parts of the world. We report a case of DPB in a Chinese patient in Singapore.

Locoregional recurrence in patients with anastomotic leakage after anterior resection for rectal carcinoma

OBJECTIVE

Anastomotic leakage is a serious complication after anterior resection for rectal carcinoma. It is controversial whether anastomotic leakage influences the rate of locoregional recurrence and therefore survival.

PATIENTS AND METHODS

The data of 940 patients with invasive rectal carcinoma stage I-III treated by curative anterior resection from 1978 to 1996 at the Department of Surgery of the University of Erlangen were analysed. Patients who received neoadjuvant or adjuvant treatment were excluded as well as patients who died postoperatively. 89 out of 814 patients (10.9%) developed an anastomotic leakage after anterior resection.

RESULTS

The rate of locoregional recurrence during the first five postoperative years of all patients was 13.6%. In patients with anastomotic leakage the rate of locoregional recurrence was 22.0%, significantly higher than in patients without anastomotic leakage which was 12.5%, (P=0.018). On multivariate Cox regression analysis anastomotic leakage was shown to be an independent risk factor for locoregional recurrence (relative risk: 1.7, CI 95%: 1.02-2.75, P=0.042). Also cancer-related survival was influenced significantly by anastomotic leakage in univariate analysis as well as in multivariate analysis (relative risk: 1.6, CI 95%: 1.1-2.2, P=0.017).

CONCLUSION

Anastomotic leakage after anterior resection for rectal carcinoma is a risk factor for locoregional recurrence and decreases cancer-related survival.

Cloning and Expression of Chinese Duck Interferon-gamma Gene

The efficacy of cytokine therapy has been demonstrated in several viral diseases. Interferon-gamma is a cytokine that has potent antiviral property and immunomodulatory activity. To investigate the role of IFN-gamma in viral clearance during natural infection and to define the antiviral mechanism, DHBV-infected ducks was used as an animal model. To clone, express, and develop the method of quantifying DuIFN-gamma gene transcription and expression, DuIFN -gamma cDNA was amplified by RT-PCR from PHA stimulated duck PBMC. Recombinant plasmid expressing DuIFN-gamma was used to transfect COS-7, and the cell culture supernatant was analyzed by CPE inhibitory assay and MTT methods to determine the antiviral titer of IFN-gamma. The GST-DuIFN-gamma fusion protein was expressed in E.coli and purified using the GST sepharose 4B. Results indicated that the supernatant collected from COS-7 cells transfected with DuIFN-gamma cDNA was able to prevent duck fibroblasts from VSV induced CPE in a dose dependent manner. An anti-DuIFN-gamma antibody neutralized this antiviral activity.

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China

OBJECTIVE

To test the efficacy of locally produced Vi vaccine over a time period of longer than one year.

METHODS

A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests).

FINDINGS

After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries.

CONCLUSION

The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Parents' psychosocial problems influencing the continuity of early intervention treatment in children with developmental delay

Developmental delay is a chronic disorder, which has a significant and continuing impact on the developmental progress of children. Whether the developmentally delayed children have continuous early intervention treatment is important for the success of early intervention. Professionals in early intervention services have been encouraged to understand parents' psychosocial problems and to further enhance their understanding of care for their delayed children. The purposes of this study were two-fold. The first was to identify the parents' psychosocial problems. The second purpose was to find parents' psychosocial variables that could be used to significantly discriminate whether the retarded children have continuously received treatment programs. A questionnaire to investigate parents' psychosocial problems was implemented. It mainly consisted of twenty descriptive items concerning parents' psychosocial conditions. Parents used a four-point Likert scale to rate the likelihood of the items. Parents also responded as to whether their child had received treatments continuously. Subjects were the parents of children who were diagnosed to have developmental delay. Factor analysis and discriminant analysis was used for statistical data examination. Analyzed data were from 207 completely finished questionnaires. Six parents' psychosocial factors were extracted via factor analysis, and they accounted for 46.9% of the variance of the twenty items. The factors were identified as family income, family members' relationships, caring skills, supporting resources, acceptance of the retarded child, and self-psychological adaptation. About half of the children had received treatment continuously. Discriminant analysis revealed that family income was crucial to parents' capacity to meet the needs for treatment.

Characterization of a thrombin-like enzyme from the venom of Trimeresurus jerdonii

From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, called jerdonobin, was purified by DEAE A-25 ion-exchange chromatography, Sephadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypeptide chain with a molecular weight of 38,000. The NH(2)-terminal amino acid sequence of jerdonobin has great homology with venom thrombin-like enzymes documented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg. The fibrinopeptides released, identified by HPLC, consisted of fibrinopeptide A and a small amount of fibrinopepide B. The activities of the enzyme were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it, indicating it is venom serine protease.

Linkage and association of tumor necrosis factor receptor 2 locus with hypertension, hypercholesterolemia and plasma shed receptor

Tumor necrosis factor (TNF) receptor 2 (TNF-R2) has been implicated in insulin resistance and metabolic syndrome disorders, one of which is hypertension (HT). We therefore decided to test markers in and near the TNF-R2 gene (TNFRSF1B) for linkage and association with HT, as well as hypercholesterolemia, and plasma levels of the shed soluble receptor (sTNF-R2). The linkage study, which involved 200 HT Anglo-Celtic Caucasian sibpairs, indicated a sharp, significant linkage peak centered at TNFRSF1B (multipoint maximum LOD score = 2. 6 and 3.1 by weighted and unweighted MAPMAKER/SIBS, respectively; two-point LOD scores = 2.9 and 3.9 by weighted and unweighted SPLINK, respectively; P = 10(-4) by identical-by-state chi(2)). The case-control study in 134 unrelated HTs who were the offspring of two HT parents and 197 normotensives (NTs) whose parents were both NTs, indicated possible association of TNFRSF1B with HT by haplotype analysis (P = 0.008). Plasma sTNF-R2 was elevated in HTs (P < 0. 0001) and showed a correlation with systolic and diastolic blood pressure (BP) (P < 0.0002). A genotypic effect of TNFRSF1B on plasma sTNF-R2, as well as total, low and high density lipoprotein cholesterol, and diastolic BP was observed. These observations are consistent with a scheme leading to raised BP and hypercholesterolemia. In conclusion, TNFRSF1B may be a candidate gene for HT and other metabolic syndrome abnormalities.

The dose-response of intrathecal sufentanil added to bupivacaine for labor analgesia

BACKGROUND

Regional analgesia for labor often is initiated with an intrathecal injection of a local anesthetic and opioid. The purpose of this prospective, randomized, blinded study was to determine the optimal dose of intrathecal sufentanil when combined with 2.5 mg bupivacaine for labor analgesia.

METHODS

One hundred seventy parous parturients with cervical dilation between 3-5 cm were randomized to receive intrathecal 0 (control), 2.5, 5.0, 7.5, or 10.0 microg sufentanil combined with 2.5 mg bupivacaine, followed by a lidocaine epidural test dose, for initiation of analgesia (34 patients in each group). Visual analog scores and the presence of nausea, vomiting, and pruritus were determined every 15 min until the patient requested additional analgesia. Fetal heart rate tracings were compared between groups.

RESULTS

Groups were similar for age, height, weight, oxytocin dose, duration of labor, and baseline visual analog scores. Duration of action was significantly shorter for control patients (39 +/- 25 min [mean +/- SD]) compared with those administered sufentanil, all doses (93 +/- 32, 93 +/- 47, 94 +/- 33, 97 +/- 39 min), but was not different among groups administered 2.5, 5.0, 7.5, or 10.0 microg sufentanil. More patients who received 10 microg sufentanil reported nausea and vomiting than did control patients. The severity of pruritus increased with administration of 7.5 and 10.0 microg sufentanil. There was no difference in fetal heart rate changes among groups.

CONCLUSIONS

Intrathecal bupivacaine (2.5 mg) without sufentanil did not provide satisfactory analgesia for parous patients. However, bupivacaine combined with 2.5 microg sufentanil provided analgesia comparable to higher doses, with a lower incidence of nausea and vomiting and less severe pruritus.

[Effects of simulated weightlessness on carbohydrate intake and serum lipids]

OBJECTIVE

To observe the effects of simulated weightlessness on the nutritional state and contents of serum lipids in human.

METHOD

Eighteen healthy men were exposed to 21 d bed rest with -6 degrees head down tilt (HDT -6 degrees). Nutrients intake was calculated and the lipids levels were determined on the first, eleventh and twenty-first day.

RESULT

Intake of the three main nutrients, carbohydrates, protein and fat met the physiological requirement essentially, but carbohydrates intake was significantly reduced in the second week. There were no significant differences among the lipid levels during different periods.

CONCLUSION

Simulated weightlessness may exert a short-term and reversible influence on human nutritional intake except for lipids.

Cloning and characterization of a novel nuclease from shrimp hepatopancreas, and prediction of its active site

Approximately 95% of the amino acid sequence of a shrimp (Penaeus japonicus) nuclease was derived from protease-digested peptides. A 1461-base cDNA for the nuclease was amplified and sequenced with degenerate primers based on the amino acid sequence and then specific primers by 3' and 5' RACE (rapid amplification of cDNA ends). It contains an open reading frame encoding a putative 21-residue signal peptide and a 381-residue mature protein. The N-terminus of the enzyme is pyroglutamate, deduced from composition and matrix-assisted laser desorption ionization-time-of-flight MS analyses, and confirmed by a glutamine residue in the cDNA sequence. The enzyme has 11 Cys residues, forming five intramolecular disulphides. The eleventh Cys residue was linked to a thiol compound with an estimated molecular mass of between 500 and 700 Da. A sequence similarity search revealed no homologous proteins but residues 205-255 shared a conserved active-site motif within a distinct group of nucleases. His(211) in this conserved motif was shown to be very important in catalysis by site-specific modification with (14)C-labelled iodoacetate. The shrimp nuclease, previously designated DNase I, does indeed possess a low level of hydrolytic activity towards RNA in the presence of Mg(2+) and Ca(2+). The conservation of functionally important residues during distant evolution might imply that the catalytic mechanisms are similar in these nucleases, which should be classified in one subfamily. Finally, an active-site structure for shrimp nuclease was proposed on the basis of published structural data and the results of mutational and biochemical analyses of Serratia nuclease.

[Diagnosis of nasal sinus fractures and its emergency management: 70 cases report]

OBJECTIVE

To study and improve the diagnosis and treatment level of nasal sinus fractures in the emergency.

METHOD

70 patients suffered from nasal sinus fractures were classified by degree of lesion. Partial of them (24 cases) were treated by Caldwell-Luc method and endoscopic sinus surgery for reducing fractures.

RESULT

The results of 22 out of 24 cases were satisfied and the other 2 good.

CONCLUSION

To better diagnose, one must pay attention to the symptoms of eyes, orbital floor and nasoethmoid sinus fracture and other severe injuries, CT scan is also necessary for diagnosis.

Detection of circulating tumor cells in venous blood of nasopharyngeal carcinoma patients by nested reverse transcriptase-polymerase chain reaction

Nasopharyngeal carcinoma (NPC) is a radiosensitive tumor. Because of recent advances in radiation oncology, distant metastasis has become the predominant failure site after adequate radiotherapy. The purpose of this study is to establish a nested reverse transcriptase-polymerase chain reaction (RT-PCR) system and to evaluate the potential of cytokeratin 19 (CK-19) mRNA as a target for detecting micrometastasis in the blood of NPC patients. Venous blood samples from 40 patients with biopsy-proven NPC (25 previously untreated and 15 after radiotherapy) and 20 healthy volunteers were tested. We divided the 40 patients into 4 groups: cured, early stage, advanced stage, and metastasized, according to results of clinical staging work-up. Under our nested RT-PCR experimental conditions, 2 of 8 early stage patients (25.0%), 6 of 15 advanced stage patients (40%), and 6 of 8 patients with distant metastasis (75%) had CK-19 positive cells in peripheral blood (P = 0.11). No CK-19 positive cells were detected in 9 "cured" patients and 20 healthy volunteers. Our data indicated that the positive detection rate for CK-19 mRNA in peripheral blood increased as the clinical stage of disease increased, but the difference did not reach statistical significance. Longer follow-up is needed to assess the significance of CK-19 mRNA in blood, as well as its relation to subsequent metastasis and prognosis of NPC.