Immortalization of mesenchymal stem cells from bone marrow of rhesus monkey by transfection with human telomerase reverse transcriptase gene

INTRODUCTION

Our previous experiments indicated that bone marrow mesenchymal stem cells of rhesus monkey (RhBMSCs) have a low proliferative ability with a finite life span, which will hamper their application in biomedical research. Establishing an immortalized RhBMSC lineage might solve the problem.

METHODS

RhBMSCs isolated from the bone marrow of rhesus monkeys using density gradient centrifugation were purified using adherence separation. Then, the cells were steadily transfected by plasmid containing human telomerase reverse transcriptase gene (pCI-neo-hTERT). We analyzed expression of hTERT, proliferation, phenotype (SH-2, SH-3, SB-10, CD29, CD34, CD45, and HLA-DR), differentiation toward osteogenic lineage, karyotype, and tumorigenesis of transfected cells.

RESULTS

After transfection, the RhBMSCs proliferated vigorously, undergoing more than 50 population doublings (PDs). Apoptotic rate of transfected RhBMSCs at PD40 was only 4.5%, versus untransfected RhBMSCs at PD15, which was more than 33.5%. Compared with normal RhBMSC, the life span of transfected RhBMSCs was prolonged, retaining similar morphology, karyotype, and potential to differentiate into an osteogenic lineage. More than 99% of transfected RhBMSCs were positive for stem cell markers, including SH-2, SH-3, SB-10, and CD29, and negative for CD34, CD45, and HLA-DR. Furthermore, the transfected cell line was benign in nude mice tumor formation.

CONCLUSION

Our results demonstrated that hTERT gene had been transfected into RhBMSCs. The transfected RhBMSCs proliferated vigorously. Phenotype, differentiation, and karyotype of transfected RhBMSC showed no significant difference from untransfected cells. The transfected RhBMSCs are a potential cell source for transplantation as well as tissue engineering.

Transmission of porcine endogenous retrovirus to human cells in nude mouse

Xenotransplantation is associated with the risk of Porcine endogenous retrovirus (PERV) transmission, since it has been shown that PERV can infect human cells in vitro (Specke et al., Virology 285, 177-180, 2001). We evaluated the possibility of PERV infection of human cells in nude mice model. Porcine kidney cells PK15 carrying PERV and human liver cancer cells SMMC-7721 were injected separately into the right and left axilla of nude mice, respectively. Two months later, pig cytochrome oxidase II (COII) gene, PERV DNA, PERV mRNA, and PERV-Gag protein were detected in the mass formed in both axillas and in several organs of nude mice. The pig COII genes were detected in the right and left axilla, but not in other organs of nude mice implicating that the microchimerism of pig cells occurred in human SMMC-7721 cells and induced the formation of the mass. PERV gene and gag protein were detected in all mouse tissues except liver. These data indicated that (i) PERV may be transmitted from porcine to mouse cells, (ii) PERV genes and proteins were detectable in the mass formed by injection of human cells and consequently (iii) there was a possibility of PERV transmission to human cells after xenotransplantation.

Gene Expression of Manganese-Containing Superoxide Dismutase as a Biomarker of Manganese Bioavailability for Manganese Sources in Broilers

The goal of this study was to determine whether Mn-containing superoxide dismutase (MnSOD) gene expression in heart tissue would reflect differences among bioavailabilities of Mn sources earlier than other indices. Broilers were divided into 5 groups and fed a Mn-unsupplemented basal diet (control) or the basal diet supplemented with 120 mg of Mn/kg as Mn sulfate or Mn methionine E (Mn Met E), Mn amino acid B (Mn AA B), or Mn amino acid C (Mn AA C) with weak, moderate, or strong chelation strength, respectively. Heart MnSOD mRNA levels were analyzed using quantitative reverse transcription-PCR at 7, 14, or 21 d. The results showed that heart MnSOD mRNA level increased as dietary Mn level increased at any age. At 7 d, chicks fed the diet supplemented with Mn AA B had higher MnSOD mRNA levels than those fed the diet supplemented with Mn sulfate and Mn Met E, and the same tendency was observed at 14 or 21 d. The results suggest that MnSOD gene expression, which is regulated by dietary Mn at transcriptional level, could reflect differences among bio-availabilities of organic Mn sources as early as 7 d. Therefore, the estimation of relative bioavailabilities of Mn sources based on heart MnSOD mRNA level could require a shorter experimental period and a smaller number of animals, and thus less cost.

Diagnostic utility of laboratory tests in septic arthritis

BACKGROUND

Septic arthritis remains a challenging diagnosis in which the doctor often relies on laboratory tests.

OBJECTIVE

To examine the diagnostic utility of three ancillary tests--namely, white blood cells (WBC), erythrocyte sedimentation rate (ESR) and the WBC in the joint fluid (jWBC)--using likelihood ratios (LRs) and receiver operating characteristic (ROC) curves.

METHODS

This was a retrospective cohort study at the Jacobi Medical Center. Medical charts of patients who had undergone arthrocentesis were included. Patients who had "dry taps" were excluded from the study. Patients were considered to have septic arthritis if they had a positive arthrocentesis culture or operative findings. The primary outcomes of this study were the sensitivities, specificities, LR(+) and LR(-) values of the laboratory tests for septic arthritis. The performance characteristics of the laboratory tests were analysed using ROC curves.

RESULTS

156 patients were enrolled, 16 (10%) had septic arthritis. The sensitivities for WBC, ESR and jWBC were 0.75, 0.75 and 0.50, and the specificities were 0.55, 0.11 and 0.88, respectively. The LR(+) values were 1.7, 0.84 and 4.0, and the LR(-) values were 0.46, 2.4 and 0.57, respectively. In ROC curve analysis, jWBC was the best test (area under the curve (AUC) 0.75, 95% confidence interval (CI) 0.58 to 0.92), followed by WBC (AUC 0.69, 95% CI 0.57 to 0.80) and ESR (AUC 0.55, 95% CI 0.37 to 0.74). A cut-off of jWBC = 17 500 maximised sensitivity and specificity on the ROC curve.

CONCLUSIONS

jWBC was the best diagnostic test for septic arthritis, WBC and ESR were poor tests. However, no test was diagnostic, and the clinician must be careful with patients with a potential septic joint.

Immunogenicity and immune modulation of osteogenic differentiated mesenchymal stem cells from Banna minipig inbred line

Mesenchymal stem cells (MSCs) represent a good choice for cell transplantation due to their multilineage differentiation ability and low immunogenicity. Our previous in vitro studies indicated that undifferentiated swine MSCs show low immunogenicity suppressing the proliferative responses of human peripheral blood lymphocyte to several antigens. In this study, we investigated the immunogenicity and immune modulation ability of osteogenic differentiated MSCs. SLA class I (P1, P14) was detectable by reverse-transcriptase polymerase chain reaction on both differentiated and undifferentiated MSCs. SLA class II (SLA-DRA, SLA-DQA) was only detectable on differentiated MSCs mixed lymphocyte reaction assays demonstrated that both differentiated and undifferentiated MSCs failed to stimulate proliferative responses by human peripheral blood lymphocytes (hPBLs). Furthermore, as undifferentiated MSCs, osteogenic differentiated MSCs also suppressed hPBL proliferation to phytohemaglutinin.

Neonatal hearing screening: evaluation of tone-burst and click-evoked otoacoustic emission test criteria

OBJECTIVE

Click-evoked otoacoustic emissions (CEOAEs) are widely used in universal neonatal hearing screening programs. A common finding in many such programs is a relatively high false-positive rate. This is often due to infant physiological noise adversely affecting the emission recording, leading to a "refer" screening outcome. In an attempt to reduce false-positive screening outcomes related to the effects of noise on otoacoustic emission response detection, tone-burst-evoked otoacoustic emissions (TBOAEs) were included in a neonatal hearing screening program because TBOAEs may elicit a greater signal-to-noise ratio than CEOAEs. The research project compared the pass/refer rate for a CEOAE-based test using established pass/refer criteria with the pass/refer rate for screening criteria that were based on TBOAE results alone or on combined CEOAE and TEOAE results.

DESIGN

Neonates were recruited at the Hong Kong Adventist Hospital, and both CEOAEs and TBOAEs were performed. Six passing criteria were used in this study, based on CEOAEs only; CEOAEs plus 1 kHz TBOAEs; CEOAEs plus 2 kHz TBOAEs; CEOAEs plus 3 kHz TBOAEs; CEOAEs plus 1, 2, and 3 kHz TBOAEs; and TBOAEs only.

RESULTS

Data from 298 neonates (546 ears) were obtained. Criteria set 1, using CEOAEs only, demonstrated a pass rate of 79.1%, and 114 ears were referred. Criteria set 2, using CEOAEs together with TBOAEs recorded at 1 kHz, passed 39 more ears than Protocol 1, and the pass rate was 86.3%. Hence, the overall referral rate for total number of screened ears decreased by 7.2 percentage points. Criteria set 3, using CEOAEs together with TBOAEs recorded at 2 kHz, and Criteria set 4, using CEOAEs in conjunction with TBOAEs recorded at 3 kHz, gave pass rates similar to Criteria set 1. Criteria set 5, using TBOAE information at frequencies where CEOAEs were not rated as "pass," raised the pass rate from 79.1 to 87.6%, reducing the overall referral rate by 8.5 percentage points. Criteria set 6, in which neonates were screened with TBOAEs recorded at 1, 2, and 3 kHz, gave a pass rate of 78.4%, similar to results for the CEOAE-only procedure.

CONCLUSIONS

Both Criteria sets 2 and 5, which combined CEOAE and TBOAE recordings, gave significantly higher pass rates than Criteria sets 1, 3, 4, and 6. The results suggest that the introduction of combined CEOAE and TBOAE protocols may assist in the reduction of refer outcomes, and hence the false-positive rates, of neonatal hearing screening programs.

Steroid Withdrawal Increases Risk of Acute Rejection but Reduces Infection: A Meta-Analysis of 1681 Cases in Renal Transplantation

OBJECTIVE

To evaluate the safety of steroid withdrawal in renal transplantation recipients.

METHODS

These following databases were searched: Medline (1966 to September 2005), OVID (1966 to 2004), Embase (1984 to 2004), Cochrane library (issue 4, 2005), Highwire (1849 to September 2005), American Transplant Congress (2005), Chinese Biomedicine database (CBM 1994 to 2005). The safety was measured by the following factors: patient and graft survival, acute rejection, chronic rejection, infection, serum creatinine. We performed meta-analysis by using Revman 4.2.7.

RESULTS

Nine randomized clinical trials were identified to have a steroid withdrawal and a steroid continuing group. They included 1681 patients: 845 with steroid withdrawal and 836 with continuing steroid. The risk of acute rejection after steroid withdrawal was two times higher than steroid-continuing group (RR 2.05; 95% confidence interval [CI]: 1.54, 2.72; P < .00001), while the incidence of opportunistic infection and urinary tract infection of steroid withdrawal group were lower than the control group (RR 0.80; 95%CI 0.64, 1.00; P = .05 vs RR 0.74; 95%CI, 0.60, 0.92; P = .004, respectively). The graft and patient survivals, chronic rejection, and serum creatinine were similar to the steroid continuing group.

CONCLUSION

Steroid withdrawal can significantly increase the risk of acute rejection episodes, but reduces the incidence of infection to a certain extent. To prophylaxis against serious infection, steroid withdrawal is worth considering using a sufficient immunosuppressive regimen. The key point is to balance the benefit and harm for the individual recipient.

Separation, cultivation and biological characteristics of oral carcinoma-associated fibroblasts

OBJECTIVES

Carcinoma-associated fibroblasts (CAFs) have been suggested to regulate the initiation and progression of many types of solid tumors. The aim of the study was to separate, cultivate, identify oral CAFs, and to investigate their biological characteristics.

MATERIALS AND METHODS

The primary CAFs and normal fibroblasts (NFs) of the tongue were obtained by tissue culture. Then cells were dissociated by 0.25% trypsin and purified by curettage method combining with trypsinization. The cells were verified according to morphological observation and immunohistochemical staining of certain proteins. Multiple proliferation indexes and karyotype of the cells were assayed.

RESULTS

Third passage purified oral CAFs and NFs were attained successfully. The morphological characteristics of the CAFs changed significantly comparing to the NFs. The CAFs showed positive staining for vimentin, alpha-smooth muscle actin and matrix metalloproteinases-2. The proliferation and mitosis ability of the CAFs were significantly increased compared with the NFs (P < 0.05). No karyotypic abnormalities were found in the CAFs.

CONCLUSIONS

There were obvious differences in the biological characteristics between oral CAFs and NFs. The results may provide us an experimental foundation for further studies on the roles of CAFs in the initiation and progression of oral cancer.

Ab initio studies on the reaction of O2 with Ban (n=2,5) clusters

Ab initio theoretical calculations have been performed to study the reaction of O(2) with Ba(n) (n=2,5) clusters. Our results show that O(2) can easily chemisorb and dissociate on small Ba(n) clusters and there is no obvious energy barrier in the process of the dissociation. The local magnetic moment contributed by oxygen must vanish during the intermediate states before the O(2) dissociation. Correspondingly, local magnetic moment only decreases from 2 mu(B) to about 1 mu(B) if O(2) molecularly adsorbs onto Ba(5) cluster. The electronic structure analysis indicates that the charge transfer from Ba(n) cluster to O(2) as well as the orbital hybridization between the cluster and the oxygen molecule may play a key role in O(2) dissociation.

First Report of Hop stunt viroid in Apricot in China

Hop stunt viroid (HSVd), a member of the family Pospiviroidae, was first described as the causal agent of hop stunt disease in Japan. It has since been found in a wide range of hosts including herbaceous and woody hosts (e.g., hop, cucumber, grapevine, citrus, plum, peach, pear, apricot, almond, and pomegranate). It was also detected and characterized in apricot where infection appears to be latent (1). The viroid occurs frequently in apricot. In southeastern Spain, the presence of HSVd was found to infect 81% of apricot trees (2). Apricots originated in China and are extensively cultivated, but HSVd infection in this host has not been reported. In September 2005, a single symptomatic apricot tree, 'Yin Bai', one of the most popular and widely grown cultivars in China, was discovered at the Institute of Fruit Science in Changping District in Beijing, Peoples Republic of China. Observed symptoms included a number of yellow spots with an irregular border that scattered in an irregular manner over the leaf surface. Total RNA was extracted and used for return-polyacrylamide gel electrophoresis and reverse transcription-polymerase chain reaction (RT-PCR) (4). Results of both assays were positive for HSVd. A 297-bp full-length DNA fragment was amplified by RT-PCR using primers R1 (5'-GCTGGATTCTGAGAAGAGTT-3') complementary to HSVd residues 87-106 for the RT reaction, followed by R2 (5'-AACCCGGGGCTCCTTTCTCA-3') complementary to HSVd residues 67-84 and forward primer F3 (5'-AACCCGGGGCAACTCTTCTC-3') residues 79-96 for PCR. The primers are located in the strictly conserved central region of the conserved HSVd group and contain the unique endonuclease restriction site SmaI. The amplified products were cloned into pGEM-T (Promega, Madison, WI) and selected for further analysis on the basis of the results of restriction digests. Six individual clones were sequenced and three different sequences were obtained. Nucleic acid sequence (GenBank Accession No. DQ362901) obtained from one clone was 99.3% (nucleotide changes T²⁰⁶→C, C²³³→T) identical to HSVd.apr8 (GenBank Accession No. Y09349) (3). Sequence (GenBank Accession No. DQ362904) obtained from three clones was 99.7% (nucleotide change C²³³→T) and a third sequence (GenBank Accession No. DQ362905) obtained from two clones was 99.3% (nucleotide changes G¹⁰⁷→A, C²³³→T) identical to HSVd.apr8. Further investigation is necessary to determine whether the symptoms observed are associated with the viroid infection. To our knowledge, this is the first report of HSVd isolated from apricot in China. References: (1) N. Astruc et al. Eur. J. Plant Pathol. 102:837, 1996. (2) M. C. Cañzres et al. Acta Hortic. 472:581, 1998. (3) S. A. Kofalvi et al. J. Gen. Virol. 78:3177, 1997. (4) S. F. Li et al. Ann. Phytopathol. Soc. Jpn. 61:381, 1995.

Long-term effects on HEK-293 cell line after co-culture with porcine endogenous retrovirus

Xenotransplantation of pig organs, tissues, and cells bears the risk of interspecies transmission of porcine endogenous retrovirus (PERV). To evaluate the long-term effect of PERV infection on human cells, human embryonic kidney cell line HEK-293 cells were co-cultured with PERV produced by the porcine kidney PK15 cell line for 24 hours and the infected HEK-293 cells were continually cultured for 6 months. PERV-gag, pol gene and gag protein were detected in infected HEK-293 cells by PCR and immunofluorescent staining. PERV from the supernatant of infected HEK-293 cells was same as that from PK15 in morphology. The concentration of reverse transcriptase in the supernatant of infected HEK-293 cells was almost 200 times lower than that of PK15 cells. Except that infected HEK-293 cells doubled a little earlier than the control and infected cells grew in serum-free medium poorly, further study for cell morphology and growth showed no significant difference between infected HEK-293 cells and uninfected control. These results suggested although PERV from PK15 could infect human cells in vitro, there was no significant acute effect attributable to PERV infection on the growth of HEK-293 cells by 6 months culture.

Suppression of human peripheral blood lymphocyte proliferation by immortalized mesenchymal stem cells derived from bone marrow of Banna Minipig inbred-line

This study sought to investigate whether mesenchymal stem cells (MSC) derived from Banna Minipig Inbred-line (BMI-MSC) suppressed human peripheral blood lymphocyte (hPBLs) proliferation in a one-way mixed lymphocyte reaction system. BMI-MSC failed to stimulate proliferative responses by hPBLs, which were activated by allogenic endothelial cells, BMI-PBLs and non-specific mitogenic stimuli. Furthermore, BMI-MSC also suppressed proliferation of hPBLs stimulated by mismatched allogenic, as well as xenogenic PBLs, and the mitogenic stimulus ConA. The suppression occurred in dose-dependent fashion when the ratio of hPBLs to BMI-MSC varied from 1 to 5 fold; fewer, BMI-MSC (0.001 to 0.01 times) showed no obvious suppression. When BMI-MSC were added to hPBLs stimulated for 72 hours, the proliferative suppression was still evident. Addition of anti-FasL or anti-TGF-beta1 antibody attenuated the proliferative suppression, while antibody against IL-10 had no effect on it. Further immunofluorescence analysis demonstrated that FasL and TGF-beta1 constitutively expressed BMI-MSC. These findings suggest that BMI-MSC suppress hPBLs proliferation relying on FasL and TGF-beta1 mediated pathways.

First-principles studies on the reactions of O2 with silicon clusters

The reactions of an O(2) molecule with the neutral and positively charged Si(n)(n = 3-16) clusters are studied with first-principles calculations. Neutral Si(n)(n = 4,5,6,7,10,14) and charged Si(n) (+)(n = 4,5,6,7,13,15) clusters show higher inertness to O(2) molecule adsorption, which is in good agreement with experimental results. Both charge transfer and hybridizations between Si and O play an important role in the dissociative adsorption of O(2) molecule. We find that the spin triplet-single conversion of O(2) molecule is always accompanied with O(2) dissociatively chemisorbed on the Si(n) clusters.

Elderly suicide in Hong Kong--a case-controlled psychological autopsy study

OBJECTIVE

To examine some of the risk factors for late life suicide in Hong Kong Chinese using a case-controlled psychological autopsy approach.

METHOD

Informants of 70 subjects aged 60 or above who had committed suicide as well as a community sample of 100 elderly controls were interviewed. Subjects and controls were assessed for the presence of mental illness, history of suicide attempt and data on health care utilization.

RESULTS

Eighty-six per cent of suicide subjects suffered from a psychiatric problem before committing suicide, compared with 9% of control subjects. Among the psychiatric problems, major depression was the commonest diagnosis. Seventy-seven per cent of suicide subjects had consulted a doctor within 1 month of suicide. One-third of suicide subjects had a history of suicide attempt. Rates of current psychiatric diagnosis, rates of medical consultation and history of suicide attempt are all significantly higher in suicide subjects than controls.

CONCLUSION

Our findings support the view that depressive disorders and a past history of suicide attempt are risk factors of late-life suicide in the Chinese population of Hong Kong, similar to findings in western studies.

Flexible carbon nanotube membrane sensory system: a generic platform

Multi-walled carbon nanotube membrane as obtained from soft lithography-mediated selective chemical-vapor deposition template approach has been successfully integrated with flexible elastomeric polydimethylsiloxane framework to fabricate microsensing devices. Two proof-of-concept experiments, namely high-sensitivity chemical gas sensing and electrochemical detection have been performed to demonstrate its potential as a useful generic platform for general purposes sensory system.

Effect of age on acute pain perception of a standardized stimulus in the emergency department

STUDY OBJECTIVE

The study was undertaken to determine whether pain perception is different in elderly patients than in younger patients.

METHODS

A cross-sectional, observational study was conducted at 2 urban academic emergency departments. Adult patients (> or =18 years of age) who required an 18-gauge intravenous catheter as part of their ED care were eligible. Patients were excluded for the following conditions: more than one attempt at intravenous catheter placement, altered mental status, visual impairment, intoxication, distracting pain, or abnormal upper extremities. Patients were asked to indicate on a 10-cm visual analog scale (VAS) the amount of pain they had at baseline immediately before intravenous catheter placement. They were then asked to indicate on a separate VAS the amount of pain caused by intravenous catheter placement. Patients aged 65 years and older were defined a priori as elderly.

RESULTS

Of 100 patients enrolled in the study, 32 (32%) were elderly. Elderly patients reported significantly less pain than nonelderly patients (Delta = -15 mm, 95% confidence interval -26 to -4 mm). Pain of intravenous catheter placement was not associated with sex, baseline pain, site of intravenous catheter insertion, or level of training of the individual placing the intravenous catheter.

CONCLUSION

Elderly patients experienced less acute pain than their younger counterparts in response to a standardized stimulus in a clinical setting. This difference is both statistically and clinically significant. This may have clinical implications for the assessment and treatment of acute pain in the elderly.

GAMYB-like genes, flowering, and gibberellin signaling in Arabidopsis

We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley alpha-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA(1) by 11-fold and GA(4) by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.

GAMYB-like genes, flowering, and gibberellin signaling in Arabidopsis

We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley alpha-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA(1) by 11-fold and GA(4) by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.

Axillary osmidrosis treated by partial removal of the skin and subcutaneous tissue en bloc and apocrine gland subcision

BACKGROUND

Axillary osmidrosis can be treated with many methods, but local surgery is the treatment of choice.

METHODS

Forty-three patients (32 females and 11 males, average age 20.3 years) were treated by partial removal of the skin and subcutaneous tissue en bloc and follicular clipping of the adjacent area. All operations were performed with local anesthesia in an outpatient setting.

RESULTS

Follow-up ranged from 2 to 47 months (mean: 13.4 months). Forty-one patients (95%) had good results, two (5%) were fair, and none were poor. No recurrences were seen. The wound complication rate was 3.5% for axillae and 7% for patients. There were no scar contractures or limitations of arm abduction.

CONCLUSION

This combined surgical method can eliminate malodor and has a low wound complication and recurrence rate. Though the transient and conspicuous scar is the chief drawback of this method, it is a simple, safe, effective and inexpensive method for treating axillary osmidrosis.

Piezoelectric quartz crystal based label-free analysis for allergy disease

This work presents a piezoelectric (Pz) quartz crystal based label-free quantification of total IgE and allergen-specific IgE in human sera for allergy testing. An evaluation of the different brands of crystals was first initiated with respect to variability in mass sensitivity, frequency measurement reliability and stability, and surface roughness. Thereafter, for total IgE quantification. a direct assay format was adopted. By means of thioctic acid (TA) and coupling reagents, anti-human IgE antibodies were immobilized on AT-cut Pz crystals (10 MHz). The modified crystals could detect serum IgE directly corresponding to a downward frequency shift. The results showed that silver-coated crystals as compared with their gold-coated counterparts provided approximately 1.5 times higher mass detection sensitivity for total IgE in the range of 5-300 IU/ml with a linear regression line, y = 1.8957 x + 1.5603, R2 = 0.995. For the detection of allergen-specific IgE, a sandwiched assay format was used. As the allergen-modified sensor surface captured various classes of associated antibodies (IgE, IgG, etc) and interfering serum proteins as well, the initial frequency shift downwards caused by sera sample incubation would not be proportional to specific IgE levels. Thus, following sample incubation, a second incubation step with secondary anti-human IgE was added to recognize IgE from other bound substances. The frequency shift after secondary antibody binding reflected the amount of allergen-specific IgE proportionally. Compared with 10 MHz crystals, the 20 MHz counterparts provided approximately four times higher mass detection sensitivity for allergen specific IgE in the range of 0.15-17.5 IU/ml with a linear regression line, y = 50.525 x + 107.777, R2 = 0.954. Total IgE and allergen specific IgE assay results of real patients' sera using the Pz sensors agreed well with those obtained by commercially available test kits with correlation coefficient 0.96-0.98. The possibility of regenerating the quartz crystals for further re-use was also dealt with.

From malformations to molecular mechanisms in the male: three decades of research on endocrine disrupters

For three decades, we have known that estrogens alter the development of the mammalian reproductive system in predictable ways. In mice exposed prenatally to diethylstilbestrol (DES) or other estrogens, the male offspring exhibit structural malformations including cryptorchidism, epididymal cysts and retained Mullerian ducts. The estrogen-associated alterations in the genital tract phenotype can be usefully considered as a model called Developmental Estrogenization Syndrome. While estrogen treatment during critical periods of morphogenesis of the male reproductive system has been associated with these changes, the mechanisms at the molecular level are still being discovered. Parallel findings on the hormones involved in Mullerian duct regression and testicular descent have helped guide research on the mechanisms of developmental estrogenization of the male. Cellular localization of molecular signals associated with key steps in genital tract development, use of mice with gene disruption, and knowledge of the mechanisms underlying persistent changes in gene expression are beginning to provide a blue print for both the physiological role and pathological effects of estrogens in reproductive tract development. Since many of the same biological principles underlie genital tract morphogenesis in mammals, one may expect some of the same changes in males of other species exposed to estrogen during the appropriate developmental periods.

Gene imprinting in developmental toxicology: a possible interface between physiology and pathology

Gene imprinting is an epigenetic mechanism for accomplishing persistent change in gene expression. In this brief paper, we explore the mechanisms for imprinting genes and present data showing that the synthetic estrogen, diethylstilbestrol (DES) can developmentally imprint genes by changing the pattern of DNA methylation. We further discuss the implications of this and other findings for non-mutagenic aspects of developmental toxicology, and suggest ways to use this concept in modifying in vitro screening for developmental toxicants.

High-performance chiral separation of fourteen triazole fungicides by sulfated beta-cyclodextrin-mediated capillary electrophoresis

In this paper, sulfated beta-cyclodextrin-mediated capillary electrophoresis (CE) is evaluated as a new approach for the chiral separation of triazole-type fungicides. The 14 fungicides investigated were bitertanol, cyproconazole, difenoconazole, diniconazole, flutriafol, hexaconazole, myclobutanil, paclobutrazol, penconazole, propiconazole, tebuconazole, tetraconazole, triadimefon and triadimenol. Under the optimal conditions, excellent enantioseparation was achieved for all the 14 fungicides, including those fungicides containing two chiral centers. To our knowledge, this is the only system to date that offers outstanding enantiodiscrimination towards all triazole-type fungicides. The impact of the molecular structures of the triazole compounds on their migration behavior was studied. Similar to other chemical systems involving host-guest complexation, the interaction between sulfated beta-cyclodextrin and the triazole compounds was found to be affected by a variety of factors, including electrostatic force, hydrogen bonding, steric effect and hydrophobicity. These factors, coupled with the countercurrent electroosmotic flow (EOF), were believed to be the major forces behind the exceptional chiral selectivity.

A modest reduction in c-myc expression has minimal effects on cell growth and apoptosis but dramatically reduces susceptibility to Ras and Raf transformation

Dergulation of c-myc and mutation of ras genes is commonly found in many human tumors. Several lines of evidence indicate that c-Myc and oncogenic Ras cooperate in causing malignant transformation, but the mechanism of this cooperation is not understood. We set out to investigate the effect on transformation of a modest reduction in endogenous c-Myc expression, which was achieved using a c-myc heterozygous cell line constructed by targeted homologous recombination. In contrast to previous reports where c-Myc expression or activity was ablated using antisense or dominant-defective methods, use of c-myc +/- cells provides a stable and homogeneous cell culture system with a precisely defined c-Myc expression level. In addition, this approach does not suffer from nonspecific artifacts such as antisense oligonucleotide toxicity or interference of dominant-defective proteins with multiple (and often undefined) target proteins. The striking and unexpected finding communicated here is that the relatively modest 50% reduction in c-Myc expression resulted in a greater than 10-fold reduction in susceptibility to transformation by oncogenic Ras or Raf proteins. This very significant defect in transformation potential cannot be explained on the basis of a generalized cell-cycle defect, because c-myc +/- cells exhibit only a minimal (20%) reduction in proliferation. Genetic epistasis analysis indicated that c-Myc and Ras acted by independent pathways that converged to regulate the abundance of the cyclin-dependent kinase inhibitor protein p27Kip1. Anchorage deprivation elicited a strong up-regulation of p27, and a 50% reduction in c-Myc expression significantly compromised the ability of Ras to down-regulate p27. We propose that Ras and c-Myc signals cooperate to regulate the activity of cyclin D-Cdk4/6 complexes: the former by up-regulating the expression of cyclin D1 and the latter by affecting the activity of the complexes. Ectopic expression of cyclin A restored the transformation potential of c-myc +/- cells, implicating it as a downstream genetic component in the pathway. From a therapeutic standpoint, it is of interest that, although transformation appears to be very sensitive to c-Myc expression levels, much larger reductions can be tolerated without causing any significant cell cycle defects.

Detection and analysis of depolarization artifacts in rotating-compensator polarimeters

Absolute constraints, namely, the Schwarz inequality and a complementary expression derived by us, are used to obtain corresponding absolute constraints on the Fourier coefficients of the intensity transmitted through rotating-compensator polarimeters and ellipsometers. These expressions allow the investigation of artifacts that result in mixed or apparently mixed polarization states over the cross section of the beam, the averaging time of the detector, or the frequency passband of the dispersing element. Examples include multiple internal reflections or inhomogeneous strain within an element, scattered light, and other types of system and component defects that cannot be accessed by means of polarization-state data alone. We apply these results to our polarizer-sample-compensator-analyzer (PSCA) ellipsometer to illustrate capabilities. A simple analytic model is shown to give a quantitative description of depolarization in systems for which the resolution is finite and the retardation varies with wavelength.

Enantioselective sensor based on microgravimetric quartz crystal microbalance with molecularly imprinted polymer film

We report a novel quartz crystal microbalance sensor that provides enantioselectivity to dansylphenylalanine enantiomers by using a molecularly imprinted polymer film as a recognition element. The polymeric recognition thin film, imprinted with chiral dansyl-L-phenylalanine, was immobilised on a gold electrode modified with a photoactive precursor monolayer via a self-assembly process using photopolymerization. The fabricated sensor was able to discriminate between L- and D-dansylphenylalanine enantiomers in solution owing to the enantioselectivity of the imprinted sites. The enantiomeric composition of L- and D-enantiomeric mixtures could be quantitatively determined by the fabricated sensor. The detection limit is 5 micrograms mL-1 with a response range of 5-500 micrograms mL-1 at pH 10.0. The influence of the template concentration on the sensitivity and selectivity of the synthesised polymer membranes was investigated and optimised. The surface characteristics of the polymer coating were studied by varying the pH value of the buffer solution, and a convenient regeneration process was proposed to increase the reproducibility and reusability of the sensor by flushing with pH 2.0 buffer. The selectivity and recognition mechanism of the imprinted polymer film were studied with compounds that are structurally related to the template. The method presented in this work provides a novel means of preparing highly selective and sensitive chemical sensors via self-assembly and molecularly imprinting techniques.

Microgravimetric DNA sensor based on quartz crystal microbalance: comparison of oligonucleotide immobilization methods and the application in genetic diagnosis

We report on the study of immobilization DNA probes onto quartz crystal oscillators by self-assembly technique to form variety types of mono- and multi-layered sensing films towards the realization of DNA diagnostic devices. A 18-mer DNA probe complementary to the site of genetic beta-thalassaemia mutations was immobilized on the electrodes of QCM by covalent bonding or electrostatic adsorption on polyelectrolyte films to form mono- or multi-layered sensing films by self-assembled process. Hybridization was induced by exposure of the QCMs immobilized with DNA probe to a test solution containing the target nucleic acid sequences. The kinetics of DNA probe immobilization and hybridization with the fabricated DNA sensors were studied via in-situ frequency changes. The characteristics of QCM sensors containing mono- or multi-layered DNA probe constructed by direct chemical bonding, avidin-biotin interaction or electrostatic adsorption on polyelectrolyte films were compared. Results indicated that the DNA sensing films fabricated by immobilization of biotinylated DNA probe to avidin provide fast sensor response and high hybridization efficiencies. The effects of ionic strength of the buffer solution and the concentration of target nucleic acid used in hybridization were also studied. The fabricated DNA biosensor was used to detect a set of real samples. We conclude that the microgravimetric DNA sensor with its direct detection of amplified products provide a rapid, low cost and convenient diagnostic method for genetic disease.

Disposable, low cost, silver-coated, piezoelectric quartz crystal biosensor and electrode protection

The use of a commercial, silver-coated, piezoelectric quartz crystal as a disposable, low cost and reliable immunosensor is presented. The protection of the silver electrode from undesirable oxidation was achieved by polystyrene or carboxy-poly(vinyl chloride) (PVC-COOH) modification. In addition to serving as protection for the electrode, polymer films provided a substrate for antibody immobilization by either physical adsorption or covalent linkage. Polystyrene modification showed an additional advantage of improvement of surface smoothness. The atomic force microscope (AFM) and scanning electron microscope (SEM) were used to evaluate the morphologies of polymer films obtained by dip or drop coating techniques. It was found that drop coating provided more significant improvement in surface smoothness than dip coating, and the resulting sensor surfaces were more suitable for in situ liquid phase assay. Although PVC-COOH-modified sensors were not suitable for liquid phase assay because of the high surface roughness, the covalent linkages (amide bonds) between antibodies and -COOH groups in the polymer film offered better sensor performance in ex situ assay in terms of a higher antibody binding capacity and better antigen detection sensitivity.

Acetaminophen and ibuprofen dosing by parents

BACKGROUND

Acetaminophen and ibuprofen are two of the most commonly used medications in children. It is our experience that parents often misdose these medications. Misdosing may lead to unintended toxicity or inadequate symptomatic improvement. There are limited data on the extent of misdosing of these antipyretics. We sought to determine the prevalence of and risk factors for inaccurate dosing by parents seeking care for their children in the emergency department (ED).

METHODS

A cross-sectional observational study was performed in an urban academic pediatric ED. Two hundred patients 10 years of age and younger who were given a known dose of acetaminophen or ibuprofen in the 24 hours prior to the ED visit were enrolled. The treating physician completed a questionnaire for each patient. Caregivers were asked about quantity and frequency of antipyretic use prior to the ED visit, the source of information used to determine dosage, and which factor (eg, age, sex, height, weight, height of fever, severity of illness) they considered most important in determining the correct dosage of medication. Doses of 10 to 15 mg/kg for acetaminophen and 5 to 10 mg/kg for ibuprofen were considered accurate.

RESULTS

Overall, 51% of patients received an inaccurate dose of medication, including 62% of patients given acetaminophen and 26% of patients given ibuprofen. Infants < 1 year old were more likely to receive an inaccurate dose (RR 1.40, P < 0.04, 95% CI = 1.06-1.86). Caregivers who stated that medication dosage was based on weight were less likely to give an inaccurate dose of medication (RR 0.71, P < 0.03, 95% CI = 0.52-0.97).

CONCLUSIONS

Over half of the caregivers surveyed gave an inaccurate dose of acetaminophen or ibuprofen, particularly to infants. Caregivers who reported that antipyretic dosage was based on weight were less likely to misdose medication, suggesting a valuable role for patient education.

Electrocardiographic diagnosis of myocardial infarction in patients with left bundle branch block

STUDY OBJECTIVE

To validate ECG criteria previously proposed by Sgarbossa et al for the detection of myocardial infarction (MI) in patients with left bundle branch block (LBBB) and suspected ischemia.

METHODS

A retrospective cohort study was performed at an urban teaching hospital. All patients admitted with suspected ischemia and LBBB were eligible. MI was defined as an elevated creatine kinase (CK) isoenzyme MB (>14 IU/L) that was at least 5% of total CK level. ECGs were interpreted by 2 physicians blinded to patient outcome. Interpreters were asked to rate ECGs for the presence of each of the 3 criteria proposed by Sgarbossa et al: (1) ST-segment elevation greater than or equal to 1 mm concordant with the QRS complex; (2) ST-segment elevation greater than or equal to 5 mm discordant with the QRS complex; and (3) ST-segment depression in leads V(1) through V(3). Interobserver agreement was assessed.

RESULTS

Of 190 eligible patients, 25 (13%) had MI. Sensitivities of the 3 criteria varied from 0 to 16%, with specificities of 93% to 100%. Only the first criterion demonstrated a clinically useful likelihood ratio (positive likelihood ratio=16 [95% confidence interval 4 to >100]). Patients with new LBBB were more likely to have MI (relative risk=5. 1 [95% confidence interval 2.6 to 10]). Interobserver agreement among ECG interpreters ranged from 93% to 98%.

CONCLUSION

The criteria of Sgarbossa et al cannot be used to exclude MI in patients with LBBB because of low sensitivities and poor negative likelihood ratios. ST-segment elevation concordant with the QRS complex had a high positive likelihood ratio for identification of MI. Patients with new LBBB and suspected ischemia are 5 times more likely to have MI than patients with LBBB of chronic or unknown duration.

Derivatization, extraction and concentration of amino acids and peptides by using organic/aqueous phases in capillary electrophoresis with fluorescence detection

We report a novel method that facilitates sample pretreatment and detection in amino acid analysis by coupling solvent extraction with capillary electrophoresis. Amino acids and peptides were fluorescently labeled, concentrated into an organic solvent, and then separated by capillary zone electrophoresis with fluorescence detection. To achieve this, acetophenone was first employed to dissolve the derivatizing reagent, fluorescamine. The products, which possessed both hydrophilic and hydrophobic moieties, could be extracted and concentrated into the organic phase by suppressing the deprotonation of carboxyl groups, thus enhancing the hydrophobicity of the resulting molecules through pH modification in the aqueous solution. Furthermore, by fine-tuning the pH value, individual amino acids and short peptide molecules could be separated selectively from the sample bulk. This convenient, chemically controllable concentration technique may be useful in sample concentration and purification of biologically related samples such as amino acids and short peptides.

[The RYR1 genotype of Chinese inbred pigs]

OBJECTIVE

Porcine stress syndrome (PSS) is one kind of molecular genetics defect diseases of pig which will cause malignant hyperthermia syndrome (MHS) and is the first index should be excluded in screening of a pig species for xenotransplantation. It was reported that mutation of pig rynodine receptor(RYR1) gene is the main reason for PSS. In this study, RYR1 genotypes of the Chinese Banna mini pig inbred line and inbreeding closed colony Wuzhishan pig were investigated with polymerase chain reaction-restriction endonuclease fragment length polymorphism (PCR-RFLP) technique.

METHODS

Antevenocaval whole blood samples were collected from 50 Banna mini-pig inbred-line(BMI), 15 inbreeding Wuzhishan pig (WZSP) and 25 Neijiang pigs (NJP) as negative control, the primer were designed and synthesized, PCR reaction was conducted following the sequence of 94 degrees C (1 min), 58 degrees C (1 min) and 72 degrees C (1 min) for 30 cycles. The PCR products were digested with restriction endonuclease HhaI and then electrophoresis check.

RESULTS

A 659 bp DNA fragment was amplified with these two primers, the HALNN sample fragment was cut into fragments as 493 bp and 166 bp individually after the digestion, indicates no point mutation at site 1,843 in RYR1 gene in all tested BMI pig and WZSP. Namely, the RYR1 genotype of 50 cases of BMI and 15 cases of WZSP were HALNN, therefore their phenotype is PSS negative.

CONCLUSION

It indicates that the genotype of Banna mini pig inbred line and inbreeding Wuzhishan pig are HALNN therefore PSS absolutely negative, the group penetrance is 0. This is consistent with experimental observation. It suggests that Banna mini pig inbred line and inbreeding Wuzhishan pig may be the alternative donor for xenotransplantation.

Simultaneous chiral separation of triadimefon and triadimenol by sulfated beta-cyclodextrin-mediated capillary electrophoresis

Enantiomeric separation of two triazole fungicides, triadimefon and triadimenol, was investigated in sulfated beta-cyclodextrin (sulfated beta-CD)-mediated capillary electrophoresis (CE) systems. It was found that, at pH 2-4, sulfated beta-CD exhibited strong chiral recognition towards both triadimefon and triadimenol. The enantiorecognition was believed to result from the multiple interactions between sulfated beta-CD and the analytes, which included inclusion effect, electrostatic interaction, and hydrogen bonding. Under optimal conditions (phosphate buffer with 2% sulfated beta-CD, pH 2.5), simultaneous resolution of all chiral isomers of triadimefon and triadimenol was achieved in less than half an hour. In conjunction with solvent extraction and subsequent enrichment by solid-phase extraction (SPE), this new enantioseparation method was applied successfully in the study of stereoselectivity associated with the biotransformation of triadimefon to triadimenol by soil microorganisms. The present methodology was superior to the commonly adopted chiral gas chromatography (GC) approach in that a very mild procedure was involved from sample extraction to the ultimate chiral separation. Thus, the disturbance of the enantiomeric distribution patterns of the original soil samples by heat stress was an unlikely scenario. Furthermore, it was discovered that, owing to the unique selectivity of the present separation strategy, there was virtually no interference from the soil matrix, which led to improvements in both sensitivity and selectivity in real sample determination.

Separation of polymerase chain reaction amplified bird genes by capillary electrophoresis

Female birds possess one Z and one W chromosome, whereas male birds possess two identical Z chromosomes. Thus, the presence of a W genetic marker is diagnostic of the female sex. Capillary electrophoresis with buffer containing an entangled solution of hydroxyethylcellulose was used to separate the polymerase chain reaction (PCR) amplified bird sexing genes CHD-Z and CHD-W. The relative standard deviations (RSD) were less than 0.6% for the male genes and less than 0.4% for the female genes for six runs and detection limits of 0.1 ng/microL were obtained with laser-induced fluorescence (LIF) detection. Using a DNA ladder and theoretical models for DNA separation in sieving media, the sizes of the two bird genes were determined.

Prospective confirmation of low arrest rates among intoxicated drivers in motor vehicle crashes

OBJECTIVE

Several states have legally sanctioned or mandated physician reporting of drivers who were driving while intoxicated (DWI). Valid prospective evidence demonstrating extremely poor performance of the criminal justice system seems ethically and scientifically essential if overriding public health considerations are to abrogate the fundamental principles of patient-physician confidentiality. No such evidence is available. The authors reasoned that poor performance of the judicial system would be most evident if drivers who were DWI were not arrested under conditions selected to optimize legal intervention. The authors therefore wished to estimate the unbiased proportion of DWI drivers brought to an emergency department (ED) under these optimized conditions who escape detection by law enforcement officials.

METHODS

Prospective, consecutive cohort of drivers transported to an urban ED following a motor vehicle crash (MVC). Conditions selected to optimize legal intervention included: police at scene; inebriation of driver clinically evident to out-of-hospital personnel; and confirmatory blood ethanol level > or =100 mg/dL (> or =22 mmol/L). Main outcome measure was arrest for DWI.

RESULTS

Of 294 drivers in MVCs, 270 had ethanol levels, of whom 18 met criteria for optimum likelihood of legal intervention. Of these, 22% were arrested for DWI (95% CI = 6% to 48%). Adjustment for missing data, under assumptions designed to maximize arrest frequency for DWI, did not materially alter these findings. No patients were lost to follow-up.

CONCLUSION

These findings prospectively confirm that, even under conditions selected to optimize detection by law enforcement officials, only about one of every five drivers who were DWI and were brought to an ED following an MVC-and almost certainly no more than a minority-comes to the attention of the criminal justice system.

Coupling of solvent semimicroextraction with capillary electrophoresis using ethyl acetate as sample matrix

This paper reports a strategy to couple liquid-liquid semimicroextraction (LLsME) with capillary electrophoresis (CE) based on a newly introduced on-column decomposable sample matrix, ethyl acetate (EA). LLsME was performed in volumetric flasks of 100 mL. Samples containing an aqueous phase were first saturated with EA. Then, an extra 500 microL of EA was added to extract the samples. Sample injection in CE could be made in hydrodynamic mode by dipping the injection end of the capillary into the organic (EA) phase in the volumetric flasks. As a demonstration, alkylphenones in water samples were extracted by LLsME into EA and subjected to separation by micellar electrokinetic chromatography (MEKC). Alkylphenones of C8-C12 with concentrations of about 10 ppb can be concentrated and detected after extraction; extraction efficiencies range from 72- to 334-fold. Linearity of extraction was determined and the effect on reproducibility by spiking an internal standard was studied. The method developed is time-saving and requires no further special experimental device other than a basic CE setup. Therefore, it would be readily acceptable for routine analysis, especially in analytical laboratories dealing with environmental samples.

High-speed chiral separations on microchip electrophoresis devices

High-speed electrophoretic chiral separations have been successfully performed in a microfabricated device by employing cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). Utilizing short separation channels and relatively high field strengths in combination with small volume-defined injection plugs, and operating in counter-electroosmotic flow conditions, fast and efficient separations of fluorescein insothiocyanate (FITC)-labeled amino acid enantiomers were obtained. Analysis time ranged from 75 s for the most basic amino acids to 160 s for the most acidic ones with associated efficiencies from 7000 up to 28 000 effective plates (100 000 to 395 000 plates/m). Buffer parameters were varied in order to study the effect on chiral resolution. A buffer system consisting of 100 mM borate (pH 9.4), 30 mM of SDS, and 10 mM gamma-CD as chiral selector provided adequate resolution of the majority of FITC-amino acid enantiomers tested.

HCPTPA, a protein tyrosine phosphatase that regulates vascular endothelial growth factor receptor-mediated signal transduction and biological activity

Angiogenesis is a tightly controlled process in which signaling by the receptors for vascular endothelial growth factor (VEGF) plays a key role. In order to define signaling pathways downstream of VEGF receptors (VEGFR), the kinase domain of VEGFR2 (Flk-1) was used as a bait to screen a human fetal heart library in the yeast two-hybrid system. One of the signaling molecules identified in this effort was HCPTPA, a low molecular weight, cytoplasmic protein tyrosine phosphatase. Although HCPTPA possesses no identifiable phosphotyrosine binding domains (i.e. SH2 or phosphotyrosine binding domains), it bound specifically to active, autophosphorylated VEGFR2 but not to a mutated, kinase-inactive VEGFR2. Recombinant VEGFR2 and endogenous VEGFR2 were substrates for recombinant HCPTPA, and HCPTPA was co-expressed with VEGFR2 in endothelial cell lines, suggesting that HCPTPA may be a negative regulator of VEGFR2 signal transduction. To pursue this possibility, an adenovirus directing the expression of HCPTPA was constructed. When used to infect cultured endothelial cells, this adenovirus directed high level expression of HCPTPA that resulted in impairment of VEGF-mediated VEGFR2 autophosphorylation and mitogen-activated protein kinase activation. Adenovirus-mediated overexpression of HCPTPA also inhibited VEGF-induced cellular responses (endothelial cell migration and proliferation) and inhibited angiogenesis in the rat aortic ring assay. Taken together, these findings indicate that HCPTPA may be an important regulator of VEGF-mediated signaling and biological activity. Potential interactions with other signaling pathways and possible therapeutic implications are discussed.