Multi-epitope schistosome vaccine candidates tested for protective immunogenicity in mice

The major challenge in the development of anti-schistosome vaccines is to use defined antigens to stimulate an appropriate immune response that leads to resistance. Several promising candidate vaccine antigens including the glycolytic enzyme triose-phosphate isomerase (SmTPI), a 28 kDa glutathione-S-transferase (Sm28), the myofibrilar protein paramyosin (Sm97), an integral membrane protein (Sm23) and calpain (Smcalpain) have been characterised and their primary sequences derived for Schistosoma mansoni. Furthermore, sequences are available for synthetic peptides mimicking epitopes on these molecules capable of inducing schistosome-specific T- and B-cell responses. These schistosome vaccine candidates have generally been tested with varying degrees of success as single components, with only one report of the use of a multivalent antigen or multi-epitope approach. We describe the assembly of multiple defined and different epitopes of S. mansoni into a variety of single covalent structures; these included a DNA vaccine encoding different epitopes in tandem, the polyprotein itself that is encoded by this DNA and branched synthetic peptide epitope-based polymers in which the individual epitopes are pendant from an inert backbone. Each of the vaccine constructs examined, with the exception of the DNA vaccine, generated antibodies that were capable of binding to a tandem sequence of the epitopes. Although these results were encouraging, none of the constructs protected animals from subsequent challenge infection, indicating that the immune responses elicited were inadequate or inappropriate for parasite killing in vivo.

Prenylation-dependent association of protein-tyrosine phosphatases PRL-1, -2, and -3 with the plasma membrane and the early endosome

PRL-1, -2, and -3 represent a novel class of protein-tyrosine phosphatase with a C-terminal prenylation motif. Although PRL-1 has been suggested to be associated with the nucleus, the presence of three highly homologous members and the existence of a prenylation motif call for a more detailed examination of their subcellular localization. In the present study, we first demonstrate that mouse PRL-1, -2, and -3 are indeed prenylated. Examination of N-terminal epitope-tagged PRL-1, -2, and -3 expressed in transiently transfected cells suggests that PRL-1, -2, and -3 are present on the plasma membrane and intracellular punctate structures. Stable Chinese hamster ovary cells expressing PRL-1 and -3 in an inducible manner were established. When cells were treated with brefeldin A, PRL-1 and -3 accumulated in a collapsed compact structure around the microtubule-organizing center. Furthermore, PRL-1 and -3 redistributed into swollen vacuole-like structures when cells were treated with wortmannin. These characteristics of PRL-1 and -3 are typical for endosomal proteins. Electron microscope immunogold labeling reveals that PRL-1 and -3 are indeed associated with the plasma membrane and the early endosomal compartment. Expression of PRL-3 is detected in the epithelial cells of the small intestine, where PRL-3 is present in punctate structures in the cytoplasm. When cells are treated with FTI-277, a selective farnesyltransferase inhibitor, PRL-1, -2, and -3 shifted into the nucleus. Furthermore, a mutant form of PRL-2 lacking the C-terminal prenylation signal is associated with the nucleus. These results establish that the primary association of PRL-1, -2, and -3 with the membrane of the cell surface and the early endosome is dependent on their prenylation and that nuclear localization of these proteins may be triggered by a regulatory event that inhibits their prenylation.

RGS proteins inhibit Xwnt-8 signaling in Xenopus embryonic development

RGS family members are GTPase activating proteins (GAPs) that antagonize signaling by heterotrimeric G proteins. Injection of Xenopus embryos with RNA encoding rat RGS4 (rRGS4), a GAP for G(i) and G(q), resulted in shortened trunks and decreased skeletal muscle. This phenotype is nearly identical to the effect of injection of either frzb or dominant negative Xwnt-8. Injection of human RGS2, which selectively deactivates G(q), had similar effects. rRGS4 inhibited the ability of early Xwnt-8 but not Xdsh misexpression to cause axis duplication. This effect is distinct from axin family members that contain RGS-like domains but act downstream of Xdsh. We identified two Xenopus RGS4 homologs, one of which, Xrgs4a, was expressed as a Spemann organizer component. Injection of Xenopus embryos with Xrgs4a also resulted in shortened trunks and decreased skeletal muscle. These results suggest that RGS proteins modulate Xwnt-8 signaling by attenuating the function of a G protein.

Phosphorylation of myosin light chain kinase by p21-activated kinase PAK2

Phosphorylation of myosin II regulatory light chains (RLC) by Ca(2+)/calmodulin-dependent myosin light chain kinase (MLCK) is a critical step in the initiation of smooth muscle and non-muscle cell contraction. Post-translational modifications to MLCK down-regulate enzyme activity, suppressing RLC phosphorylation, myosin II activation, and tension development. Here we report that PAK2, a member of the Rho family of GTPase-dependent kinases, regulates isometric tension development and myosin II RLC phosphorylation in saponin permeabilized endothelial monolayers. PAK2 blunts tension development by 75% while inhibiting diphosphorylation of myosin II RLC. Cdc42-activated placenta and recombinant, constitutively active PAK2 phosphorylate MLCK in vitro with a stoichiometry of 1.71 +/- 0. 21 mol of PO(4)/mol of MLCK. This phosphorylation inhibits MLCK phosphorylation of myosin II RLC. PAK2 catalyzes MLCK phosphorylation on serine residues 439 and 991. Binding calmodulin to MLCK blocks phosphorylation of Ser-991 by PAK2. These results demonstrate that PAK2 can directly phosphorylate MLCK, inhibiting its activity and limiting the development of isometric tension.

Determination of intermediate biomarker expression levels by quantitative reverse transcription-polymerase chain reaction in oral mucosa of cancer patients treated with liarozole

Liarozole is a 1-substituted imidazole derivative that inhibits cytochrome P450 activity and increases endogenous plasma concentrations of retinoid acid (RA). We have previously demonstrated that RA down-modulates transforming growth factor (TGF)-alpha and epidermal growth factor receptor (EGFR) levels in head and neck squamous cell carcinoma by decreasing the transcription rate of these two genes. Previous reports suggest that RA receptor (RAR)-beta levels are down-modulated in head and neck cancer and are restored by RA therapy. Cellular RA-binding protein (CRABP)-II is up-regulated by RA and appears to modulate intracellular RA metabolism. In conjunction with a Phase I clinical trial, total intact RNA was extracted from oral cavity mucosa biopsied from 17 patients with advanced malignancies, before and after treatment with a 4-week course of liarozole. To analyze these limited quantities of total RNA (as little as 0.6 microg/sample), a quantitative reverse transcription-PCR assay was developed using delayed dropping of the 5' beta-actin primer to amplify the highly abundant beta-actin gene as an internal control. We used this method to determine the expression levels of TGF-alpha, EGFR, RAR-beta, and CRABP-II before and after treatment. There was a trend toward elevation of RAR-beta levels in oral mucosa after liarozole therapy (P = 0.107), whereas TGF-alpha, EGFR, and CRABP-II were not modulated by systemic liarozole treatment. These results suggest that liarozole may up-regulate RAR-beta in tissues from cancer patients and that expression levels of potential intermediate biomarkers may be determined in small tissue biopsies using a quantitative reverse transcription-PCR assay.

Agouti-related protein-like immunoreactivity: characterization of release from hypothalamic tissue and presence in serum

A novel RIA was used to examine the release of agouti-related protein-like immunoreactivity (AGRP-LI) from perfused rat hypothalamic tissue slices and to characterize AGRP-LI in rat serum. A continuous low level basal AGRP-LI release was observed from hypothalami of rats fed ad libitum before the rats were killed. Basal AGRP-LI release was 3-fold greater in rats fasted 48 h. In fasted animals leptin dose-dependently suppressed basal AGRP-LI release. In fed animals no change in basal AGRP-LI release was detected in response to 10(-6) M alpha-MSH, orexin B, melanin-concentrating hormone, or serotonin. HPLC analysis of AGRP-LI in rat serum identified a single peak that eluted in close proximity to synthetic AGRP (87-132) and mouse [Leu127Pro]AGRP and that was identical to the peak seen in hypothalamic and adrenal tissue extracts. The serum concentration of AGRP-LI in rats fed ad libitum was 0.865+/-0.323 nmol/liter (mean +/- SE). Food deprivation resulted in a slow, but statistically significant rise in serum immunoreactivity at 48 h [1.174+/-0.118 nmol/liter (mean +/- SE)]. Bilateral adrenalectomy did not change serum levels of AGRP-LI. These studies demonstrate that in the rat there are different levels of basal hypothalamic AGRP-LI release in fed and fasted states and that in the fasted rat this release can be profoundly suppressed by leptin. These studies also suggest that AGRP is present in the systemic circulation of rats.

Epidermal growth factor receptor--mediated stat3 signaling blocks apoptosis in head and neck cancer

OBJECTIVES

Upregulation of epidermal growth factor receptor (EGFR) is critical for the loss of growth control in a variety of human cancers including squamous cell cancers of the head and neck (SCCHN). In these tumor cells in culture, EGFR stimulation initiates signaling via persistent activation of STAT proteins, particularly Stat3. The present study was conducted to study the association between EGFR stimulation and constitutive activation of Stat3 in SCCHN in vivo and to investigate the proliferative and apoptotic consequences of Stat3 downmodulation in SCCHN cells in vitro.

METHODS

SCCHN tumor xenografts were analyzed using electrophoretic mobility shift assay. A dominant-negative mutant Stat3 expression construct or a Stat3 antisense plasmid was transfected into SCCHN cells using lipofectamine. Cell growth and apoptosis were determined by vital dye exclusion and flow cytometry, respectively.

RESULTS

In vivo liposome-mediated gene therapy with an EGFR antisense plasmid efficiently inhibited Stat3 activation in a head and neck xenograft model. Downmodulation of Stat3 using a dominant-negative or antisense approach inhibited tumor cell growth and stimulated apoptosis.

CONCLUSIONS

These findings provide evidence that constitutively activated Stat3 is linked to EGFR signaling in SCCHN in vivo, which contributes to the loss of growth control by an anti-apoptotic mechanism.

Constitutive activation of Stat3 signaling abrogates apoptosis in squamous cell carcinogenesis in vivo

Field cancerization predisposes the upper aerodigestive tract mucosa to the formation of multiple primary tumors, when exposed to environmental carcinogens. Up-regulation of epidermal growth factor receptor occurs early in squamous cell carcinogenesis and is critical for the loss of growth control in a variety of human cancers, including head and neck squamous cell carcinomas. In these tumor cells in culture, epidermal growth factor receptor stimulation initiates signaling via persistent activation of selective STAT proteins. To determine the timing of Stat3 activation in head and neck carcinogenesis, we studied the expression and constitutive activation of Stat3 in tumors and normal mucosa from patients with head and neck cancer compared with mucosa from controls without cancer. Stat3 was up-regulated and constitutively activated in both primary human head and neck tumors as well as in normal mucosa from these cancer patients compared with control normal mucosa from patients without cancer. In vivo liposome-mediated gene therapy with a Stat3 antisense plasmid efficiently inhibited Stat3 activation, increased tumor cell apoptosis, and decreased Bcl-x(L) expression in a head and neck xenograft model. These findings provide evidence that constitutively activated Stat3 is an early event in head and neck carcinogenesis that contributes to the loss of growth control by an anti-apoptotic mechanism.

Multi-step polymer-assisted solution-phase (PASP) library synthesis of functionalized diaminobenzamides

A parallel solution-phase library synthesis of functionalized diaminobenzamides is described. The four-step library synthesis is accomplished using polymer-assisted solution-phase (PASP) synthesis techniques. This high-yielding, multi-step sequence utilizes sequestering resins for the removal of reactants, reactant by-products, and employs a resin capture/release strategy as a key library synthesis step. Step one of the sequence relies on the displacement of an activated fluoro-group from the aromatic ring of 1a, b with a variety of primary amines to introduce the first diversity position. Step two is hydrolysis of the benzoate ester to a benzoic acid which is subsequently captured on a polyamine resin, washed, and released to give 4a, b in pure form. Step three utilizes PASP resins to mediate the amide coupling of a benzoic acid with a variety of primary amines to give the aminonitrobenzamides 5a, b and introduces the second diversity position. Step four is the parallel reduction of the aminonitrobenzamides 5a, b to the functionalized diaminobenzamides 6a, b. This library synthesis proceeds with high overall purities which average 80 % over the 4-step sequence.

[Identification of antigens shared between Schistosoma japonicum and Trichinella spiralis]

Cross-reactivity was analysed between the antigen of T. spiralis muscular larvae and antigens of cercariae, liver stage schistosomula, 30 day male and female adult worms of S. japonicum by means of EITB technique. The result showed that the antigens of cercariae schistosomula, female worms except male worms, were recognized by sera from rabbits immunized with T. spiralis antigens or by sera from T. spiralis infected rabbits. The molecular weight of recognized antigens ranges from 15 to 100 kD, mainly from 50 to 70 kD. The immunized rabbit sera and the infected rabbit sera reacted with the same cross-antigens of S. japonicum. Among these schistosome stages, the cercariae showed the most cross-reactive bands, the second were the liver stage schistosomula, and 30 day female worms only showed a weak band which located at 97 kD position. Meanwhile, the anti-S. japonicum sera recognized several T. spiralis antigens which located at 34 kD and above, especially 35-38 kD. The results suggest that there are many antigens shared between T. spiralis and S. japonicum and the main cross-reactive antigens are found in the larva stages of S. japonicum and T. spiralis muscular larva. The cross-reactive antigens are different between various stages of S. japonicum and muscular larva of T. spiralis.

[An ultrastructural observation of peripheral blood neutrophils in patients with hepatitis B]

The abnormal changes of peripheral blood neutrophils in 13 patients with hepatitis B were observed under electron microscope. The morphological and structural changes of neutrophils included irregularity of shape, a large number of pseudopodia and phagocytic vacuoles, less electron dense granules, increased nuclear holes and vacuoles, etc. The present study provides the ultrastructural evidence of impaired neutrophil morphology and functions in such patients.

[Clinical application of magnetic resonance angiography in the body]

OBJECTIVE

To identify the accuracy and reliability of magnetic resonance angiography (MRA) in evaluating patients with vascular lesions in the body.

METHODS

171 patients with suspected vascular lesions in the body were examined by MRA and compared with the results of X-ray angiography (XRA) or operation.

RESULTS

MRA showed abnormal vein in 12 patients and normal in 6 corresponding to XRA or operation. MRA revealed aneurysm in 54 patients: aortic dissection (26), aortic aneurysm (15) and peripheral aneurysm (13). Two peripheral aneurysms could not only be found by MRA. The sensitivity of MRA was 97% for aneurysm lesions. The sensitivity of MRA in the diagnosis of suspicious peripheral artery stenosis in 84 patients was 95%, the specificity 89%, and the accuracy 92% in comparison with those of XRA and operation.

CONCLUSION

MRA is accurate and reliable in evaluating vascular lesion in the body and can replace XRA in many cases.

Endothelial cell retraction is induced by PAK2 monophosphorylation of myosin II

The p21-activated kinase (PAK) family includes several enzyme isoforms regulated by the GTPases Rac1 and Cdc42. PAK1, found in brain, muscle and spleen, has been implicated in triggering cytoskeletal rearrangements such as the dissolution of stress fibers and reorganization of focal complexes. The role of the more widely distributed PAK2 in controlling the cytoskeleton has been less well studied. Previous work has demonstrated that PAK2 can monophosphorylate the myosin II regulatory light chain and induce retraction of permeabilized endothelial cells. In this report we characterize PAK2's morphological and biochemical effect on intact endothelial cells utilizing microinjection of constitutively active PAK2. Under these conditions we observed a modification of the actin cytoskeleton with retraction of endothelial cell margins accompanied by an increase in monophosphorylation of myosin II. Selective inhibitors were used to analyze the mechanism of action of PAK2. Staurosporine, a direct inhibitor of PAK2, largely prevented the action of microinjected PAK2 in endothelial cells. Butanedione monoxime, a non-specific myosin ATPase inhibitor, also inhibited the effects of PAK2 implicating myosin in the changes in cytoskeletal reorganization. In contrast, KT5926, a specific inhibitor of myosin light chain kinase was ineffective in preventing the changes in morphology and the actin cytoskeleton. The additional finding that endogenous PAK2 associates with myosin II is consistent with the proposal that cell retraction and cytoskeletal rearrangements induced by microinjected PAK2 depend on the direct activation of myosin II by PAK2 monophosphorylation of the regulatory light chain.

Regulation of tumor angiogenesis by p53-induced degradation of hypoxia-inducible factor 1alpha

The switch to an angiogenic phenotype is a fundamental determinant of neoplastic growth and tumor progression. We demonstrate that homozygous deletion of the p53 tumor suppressor gene via homologous recombination in a human cancer cell line promotes the neovascularization and growth of tumor xenografts in nude mice. We find that p53 promotes Mdm2-mediated ubiquitination and proteasomal degradation of the HIF-1alpha subunit of hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor that regulates cellular energy metabolism and angiogenesis in response to oxygen deprivation. Loss of p53 in tumor cells enhances HIF-1alpha levels and augments HIF-1-dependent transcriptional activation of the vascular endothelial growth factor (VEGF) gene in response to hypoxia. Forced expression of HIF-1alpha in p53-expressing tumor cells increases hypoxia-induced VEGF expression and augments neovascularization and growth of tumor xenografts. These results indicate that amplification of normal HIF-1-dependent responses to hypoxia via loss of p53 function contributes to the angiogenic switch during tumorigenesis.

Percutaneous implantation of a Port-Catheter System using the left subclavian artery

PURPOSE

To evaluate the safety and feasibility of a percutaneous Port-Catheter System (PCS) implanted via the subclavian artery (SCA) for regional chemotherapy or chemoembolization of thoracic, abdominal, and pelvic malignant tumors.

METHODS

Percutaneous puncture of the SCA was performed in 256 patients with thoracic, abdominal, or pelvic malignant tumors; then a catheter was inserted into the target artery. After the first transcatheter chemotherapy or chemoembolization with an emulsion of lipiodol and anticancer agents, an indwelling catheter was introduced with its tip placed in the target artery and its end subcutaneously connected to a port.

RESULTS

The procedure was successfully completed in all 256 cases (100%). The indwelling catheter tip was satisfactorily placed in the target arteries in 242 cases (98%). Complications attributable to the procedure occurred in 20 (7.8%) cases, including pneumothorax (n = 10, 4%), hemothorax (n = 1, 0.4%), infections in the pocket (n = 4, 1.6%), and hematoma at the puncture site (n = 5, 2%). There were no severe sequelae or deaths. The duration of PCS usage was 1-36 months (median 9.5 months). During the course of treatment, occlusion of the target artery occurred in 20 cases (7.8%). Dislocation of the tip of the indwelling catheter occurred in 12 cases (4.7%); in 10 of the 12, the tip of the indwelling catheter was repositioned into the target artery. In all 10 cases no large symptomatic hematomas developed after the PCS was removed.

CONCLUSION

Percutaneous PCS implantation via the left SCA, a relatively new procedure, is a safe and less invasive treatment approach than surgical placement for malignancies.

GLIF3: the evolution of a guideline representation format

The Guideline Interchange Format (GLIF) is a language for structured representation of guidelines. It was developed to facilitate sharing clinical guidelines. GLIF version 2 enabled modeling a guideline as a flowchart of structured steps, representing clinical actions and decisions. However, the attributes of structured constructs were defined as text strings that could not be parsed, and such guidelines could not be used for computer-based execution that requires automatic inference. GLIF3 is a new version of GLIF designed to support computer-based execution. GLIF3 builds upon the framework set by GLIF2 but augments it by introducing several new constructs and extending GLIF2 constructs to allow a more formal definition of decision criteria, action specifications and patient data. GLIF3 enables guideline encoding at three levels: a conceptual flowchart, a computable specification that can be verified for logical consistency and completeness, and an implementable specification that can be incorporated into particular institutional information systems.

[The effects of transforming growth factor alpha and beta 1 on the proliferation of alveolar type II cells in vitro]

OBJECTIVE

To investigate the effect of transforming growth factor alpha and beta(1) (TGFalpha and beta(1)) on the proliferation of alveolar type II cells in vitro and the molecular mechanism related.

METHODS

(3)H-TdR incorporation and cell counting for the assay of cell growth; dot blot, in situ hybridization, and immunohistochemical methods for analysing the expression of cyclin D1 and cycle-dependent kinase 4 (CDK4) genes.

RESULTS

With increasing of the concentration of TGFalpha and beta(1) (0.01 ng-100 ng/ml), TGFalpha enabled to increase (3)H-TdR incorporation and the number of alveolar type II cells, while the effect of TGFbeta(1) was opposite and both effects were dose-dependent (P < 0.01). TGFalpha-treated cells decreased the expression of CDK4 mRNA, and the relevant in comparing with the control (P < 0.01). On the contrary, TGFbeta(1)-treated cells decreased the expression of CDK4 mRNA), CDK4 as well as the cyclin D1 proteins (P < 0.05).

CONCLUSION

Both TGFalpha and beta(1) were considered implicated in the regulation of proliferation of cultured alveolar type II cells isolated from the adult rats and CDK4 might be a common target against TGFalpha and beta(1) signals.

Effect of specific COX-2 inhibition in osteoarthritis of the knee: a 6 week double blind, placebo controlled pilot study of rofecoxib. Rofecoxib Osteoarthritis Pilot Study Group

OBJECTIVE

To determine the efficacy and safety of the cyclooxygenase 2 (COX-2) specific inhibitor, rofecoxib in patients with osteoarthritis (OA) of the knee.

METHODS

Rofecoxib, 25 mg or 125 mg once daily, was compared with placebo in a 6 week, double blind, parallel group, randomized, multicenter study of 219 patients with knee OA.

RESULTS

Both doses of rofecoxib produced clinically significant improvement as assessed by primary (e.g., WOMAC Pain Subscale 0-100 mm, decrease from baseline: placebo: 7.1 mm; rofecoxib 25 mg: 28.1 mm, rofecoxib 125 mg: 28.0 mm; p < 0.001 rofecoxib vs placebo) and secondary efficacy (p < 0.05) criteria compared with placebo. Clinical improvement with the 25 mg dose was similar to that with the 125 mg dose. Both rofecoxib doses were generally well tolerated.

CONCLUSION

Specific inhibition of COX-2 by 25 and 125 mg rofecoxib, administered once daily, resulted in clinically meaningful improvements in patients with OA. This study confirms that COX-2 derived prostanoids are important clinical mediators of pain and other symptoms of knee OA and that inhibition of COX-1 is not required to provide clinical benefit.

p53 and Bax: putative death factors in taste cell turnover

The turnover of cells in renewing epithelia presents an opportunity to examine cell death pathways in adult vertebrates. In mouse lingual epithelium a typical taste receptor cell survives for 9 days, until it is killed by an unknown cascade of death factors. Apoptosis was implicated by the presence of fragmented DNA in about 8% of taste receptor cells in the vallate papilla. In using immunocytochemistry to seek putative death factors, we observed that squamous epithelial cells of the tongue were negative for Bax, a death factor in the Bcl-2 family of survival/death factors, and were also negative for p53, a tumor-suppressor protein linked to apoptosis and Bax transcription. In contrast, 8-10% of the taste receptor cells were Bax-positive, and 9-11% were p53 positive. These immunopositive taste receptor cells were more likely to display death-related morphologic defects than other receptor cells, and they frequently coexpressed p53 and Bax. In both neonatal and adult mice, the labeling of dividing cells with 5-bromo-2'-deoxyuridine indicated that all Bax-positive taste cells were at least 5 days old. On postnatal day 7, when few taste cells were old, no more than 1% of taste cells were immunopositive for either p53 or Bax. We inferred that old taste receptor cells employ p53 and Bax as part of their apoptotic death pathway. The routine expression of p53 by postmitotic, aged taste cells broadens the conventional view that p53 is restricted to mitotic cells that have stress-damaged DNA. Furthermore, the scattered distribution of aged receptor cells within the taste bud excludes some explanations for stable taste signals during receptor cell turnover.

The safety profile, tolerability, and effective dose range of rofecoxib in the treatment of rheumatoid arthritis. Phase II Rofecoxib Rheumatoid Arthritis Study Group

Nonsteroidal anti-inflammatory drugs. (NSAIDs) inhibit both cyclooxygenase (COX)-1 and COX-2 isoenzymes and are effective in the treatment of inflammatory disorders. This 8-week, double-masked, placebo-controlled trial was undertaken to assess the safety profile, tolerability, and effective dose range of once-daily rofecoxib, a COX-2-specific inhibitor, in the treatment of rheumatoid arthritis (RA). After a 3- to 15-day washout of prior NSAID therapy, 658 patients were randomly allocated to receive placebo or rofecoxib 5 mg, 25 mg, or 50 mg once daily. Safety profile, tolerability, and efficacy were evaluated after 2, 4, and 8 weeks of therapy. Six hundred fifty-eight patients (168, 158, 171, and 161 in the placebo and 5-mg, 25-mg, and 50-mg rofecoxib groups, respectively) were enrolled at 79 clinical centers in the United States. Mean age was 55 years, mean duration of RA was 10 years, and 506 (77%) of the 658 patients were female. All groups had similar baseline demographic characteristics. Patients taking rofecoxib 25 and 50 mg showed significant clinical improvement compared with those taking placebo; 43.9% in the rofecoxib 25-mg group and 49.7% in the rofecoxib 50-mg group completed the treatment period and achieved an American College of Rheumatology 20 response (P = 0.025 and 0.001 vs. placebo, respectively). The 5-mg dose of rofecoxib did not differ significantly from placebo. Patients in the rofecoxib 25- and 50-mg groups showed significant improvement in key individual efficacy measurements, including patient global assessment of pain, patient and investigator global assessment of disease activity, and Stanford Health Assessment Questionnaire Disability Index (P<0.05 vs placebo). Compared with placebo, significantly fewer patients in the 25-mg and 50-mg rofecoxib groups discontinued therapy because of lack of efficacy (P = 0.02 and P = 0.032, respectively). Our results show that rofecoxib 25 and 50 mg once daily was effective and generally well-tolerated in patients with RA.

Intrathecal gadolinium-enhanced MR myelography and cisternography: a pilot study in human patients

OBJECTIVE

This study was designed to evaluate the safety, MR imaging characteristics, and clinical response to intrathecal gadopentetate dimeglumine (gadolinium) administration in human patients.

SUBJECTS AND METHODS

Eleven adult patients were included in this prospective study. Via lumbar puncture, a single dose of either 0.2 ml, 0.5 ml, or 1.0 ml of gadolinium (500 mmol/l) mixed with 5 ml of previously removed CSF was slowly injected into the lumbar subarachnoid space. Immediate and delayed MR imaging were subsequently carried out using a 1.0-T magnet.

RESULTS

No patient manifested gross behavioral changes, neurologic alterations, or seizure activity. The intrathecal gadolinium-enhanced MR myelography revealed disk herniation (n = 4), posttraumatic spinal stenosis (n = 3), postsurgical noncommunicating cyst (n = 1), myelitis (n = 1), intradural extramedullary mass formation (n = 1), and intradural vascular malformation (n = 1).

CONCLUSION

This pilot study shows the relative safety and feasibility of low-dose intrathecal gadolinium administration. The potential clinical applications include the evaluation of obstructions and communications of the subarachnoid space, spontaneous or traumatic CSF leaks, and CSF dynamics. Additional animal and human studies must be performed to further evaluate the long-term safety and to prove the clinical applications of this procedure in a larger number of subjects.

[A study of expression of p53, c-myc and PCNA in retinoblastoma]

OBJECTIVE

To investigate the expressions of p53, c-myc (oncogene) and proliferating cell nuclear antigen (PCNA) in retinoblastoma (Rb) and the relationships of the expression to the degree of differentiation and optic nerve infiltration.

METHOD

The expressions of p53, c-myc and PCNA in Rb tissues of 31 cases were analyzed by using LSAB immunohistochemical method.

RESULTS

The positive rates of p53, c-myc and PCNA in Rb were respectively 51.6%, 45.2% and 67.7% and all the expressions were significantly related to the differentiation degree of Rb (all P < 0.05). The expression of PCNA was significantly related to the optic nerve infiltration of Rb (P < 0.05). Both the expressions of p53 and c-myc in Rb were markedly correlated with the expression of PCNA (all P < 0.05).

CONCLUSIONS

The occurrence of Rb is the result of multiple gene mutations. The determinations of p53, c-myc and PCNA are of significance for evaluating the histologic characteristics and biological behavior of Rb.

[Ankylosing spondylitis in Shantou: clinical experience in fifteen years]

OBJECTIVE

To evaluate the clinical features of ankylosing spondylitis (AS) in Shantou area and improve the diagnostic level and therapeutic effect.

METHODS

Clinical and laboratory data, and the methods and effects of therapy were analyzed. Some patients were followed up.

RESULTS

94% of the cases had an insidious onset. Low back pain or discomfort, peripheral arthritis, positive "4" test and pressing tenderness over the sacroiliac joints and lumbar spine were the frequent symptoms and signs. The degree of sacroiliitis and involvement of hip and spine were related to the disease duration. However, hip joint involvement in juvenile onset AS did not relate to the disease duration. Some cases with disease duration as long as 16 years still remained at II of degree sacroiliitis. Clinical improvement was more obvious in the first two years of treatment. Although some patients came to a standstill condition after this period, yet the disease activity might still relapse with withdrawal of the treatment. The rate of adhering to the treatment for 1, 2, and over 5 years was 34.6%, 28.4%, and 10.3% respectively. The radiological changes frequently did not parallel with the clinical manifestations.

CONCLUSION

Early diagnosis is of importance in improving the prognosis of AS and adherence to slow-acting anti-rheumatic drug therapy is beneficial in disease controlling. A follow up of more than 3 years is necessary to estimate the therapeutic efficacy, and the radiological change is the key indicator. AS is a heterogenic disease and the risk factors for prognosis should be further studied.

B-cell epitopes recognized by Chinese water buffaloes (Bos buffelus) on the 22 kDa tegumental membrane-associated antigen (Sj-22) of the Asiatic bloodfluke, Schistosoma japonicum

The 22.6 kDa tegumental membrane-associated antigen of schistosomes is of recognized importance in immunity to schistosomiasis. In China, bovines are known to play an important role in the transmission of Schistosoma japonicum. Ten buffaloes (Bos buffelus) were vaccinated with a recombinant form (reSj-22) of the S. japonicum 22.6 kDa tegumental antigen (Sj-22) and the sera were used to identify and map possible linear B-cell epitopes on this molecule using a series of 18 overlapping synthetic peptides (P1-P18). Sera from all of the ten vaccinated buffaloes reacted strongly with Sj-22 in western blots and in ELISA, while sera from a further ten adjuvant (Quil A) control buffaloes did not. Four peptides (P3, P8, P9 and P10) were predominantly recognized by at least 90% of the buffalo sera. This pattern of recognition is similar to that obtained in a previous study we undertook in mice immunized with the same antigen whereby peptides 3, 8, 9 and 10 were recognized by over 80% of CBA strain mice. The peptide most frequently recognized by mice (peptide 6), and mapping to an EF-hand calcium binding domain, was recognized by six of the ten vaccinated buffaloes. The major difference between buffaloes and mice occurred with peptide 1 which was recognized very frequently by all three strains of mice tested but was only weakly recognized by three of the ten buffaloes. This study provides a valuable reference for further study on the immunity stimulated by the 22.6 kDa tegumental antigen in the murine model and a natural bovine host of Schistosomiasis japonica.

Structural insight into a quinolone-topoisomerase II-DNA complex. Further evidence for a 2:2 quinobenzoxazine-mg2+ self-assembly model formed in the presence of topoisomerase ii

Quinobenzoxazine A-62176, developed from the antibacterial fluoroquinolones, is active in vitro and in vivo against murine and human tumors. It has been previously claimed that A-62176 is a catalytic inhibitor of mammalian topoisomerase II that does not stabilize the cleaved complex. However, at low drug concentrations and pH 6-7, we have found that A-62176 can enhance the formation of the cleaved complex at certain sites. Using a photocleavage assay, mismatched sequences, and competition experiments between psorospermin and A-62176, we pinpointed the drug binding site on the DNA base pairs between positions +1 and +2 relative to the cleaved phosphodiester bonds. A 2:2 quinobenzoxazine-Mg2+ self-assembly model was previously proposed, in which one drug molecule intercalates into the DNA helix and the second drug molecule is externally bound, held to the first molecule and DNA by two Mg2+ bridges. The results of competition experiments between psorospermin and A-62176, as well as between psorospermin and A-62176 and norfloxacin, are consistent with this model and provide the first evidence that this 2:2 quinobenzoxazine-Mg2+ complex is assembled in the presence of topoisomerase II. These results also have parallel implications for the mode of binding of the quinolone antibiotics to the bacterial gyrase-DNA complex.

Contribution of melanocortin receptor exoloops to Agouti-related protein binding

Agouti-related protein (AGRP) is an endogenous antagonist of melanocortin action that functions in the hypothalamic control of feeding behavior. Although previous studies have shown that AGRP binds three of the five known subtypes of melanocortin receptor, the receptor domains participating in binding and the molecular interactions involved are presently unknown. The present studies were designed to examine the contribution of extracytoplasmic domains of the melanocortin-4 receptor (MC4R) to AGRP binding by making chimerical receptor constructs of the human melanocortin-1 receptor (MC1R; a receptor that is not inhibited by AGRP) and the human MC4R (a receptor that is potently inhibited by AGRP). Substitutions of the extracytoplasmic NH2 terminus and the first extracytoplasmic loop (exoloop) of the MC4R with homologous domains of the MC1R had no effect on AGRP (87-132) binding affinity or inhibitory activity (the ability to inhibit melanocortin-stimulated cAMP generation). In contrast, cassette substitutions of exoloops 2 and 3 of the MC4R with the homologous exoloops of the MC1R resulted in a substantial loss of AGRP binding affinity and inhibitory activity. Conversely, the exchange of exoloops 2 and 3 of the MC1R with the homologous exoloops of the MC4R was found to confer AGRP binding and inhibitory activity to the basic structure of the MC1R. Importantly, these substitutions did not affect the ability of the alpha-melanocyte stimulating hormone analogue [Nle4,D-Phe7] melanocyte stimulating hormone to bind or activate the chimeric receptors. These data indicate that exoloops 2 and 3 of the melanocortin receptors are important for AGRP binding.

[Cross reaction of Trichinella spiralis larva antigens with sera of schistosomiasis japonica]

Cross reactions of T. spiralis muscular larva antigens (TsMLA) against several sera from patients with other parasitic diseases by ELIB (enzyme-linked immunoblotting technique) were studied. The proteins of 31-100 KDa were recognized by sera of two cases of acute schistosomiasis, while proteins of 44/45, 51/53, 62/64 and 100 KDa were recognized by sera of 11 cases of chronic schistosomiasis. The proteins of 60 KDa showed varied cross reactions against sera of five kinds of patients with other parasitic diseases (filariasis, hookworm diseases, paragonimiasis, ascariasis and clonorchiasis). Only the proteins of 45 KDa were recognized by six of fifteen cases of normal human sera. All of > 29 KDa proteins were recognized by sera of rabbit infected by T. spiralis. It is suggested that there were many antigens in Trichinellen muscular larva which shared in common with several other parasites. The cross reactions of TsMLA against Schistosoma japonicum may be differentiated on the positive reaction bands of 44/45, 51/53, 62/64 and 100 KDa proteins which was specific to the chronic schistosomiasis using the TsMLA by means of ELIB.

Sequence analysis of Pasteurella multocida major outer membrane protein (OmpH) and application of synthetic peptides in vaccination of chickens against homologous strain challenge

Pasteurella multocida major outer membrane protein (OmpH) has been previously characterized as a porin. The native OmpH from strain X-73 (serotype 1) but not recombinant protein from Escherichia coli induced homologous protection in chickens. In this study OmpH sequences from 15 P. multocida serotypes as well as the CU vaccine strain were compared by sequence alignment and revealed high homology, with major variations confined to two discrete regions which were correspondingly predicted as two largest external loops. Secondary structures of OmpHs were predicted by sequence alignment of OmpHs with well defined porins and analyses of amphiphilicity, hydrophobic moment and antigenic index plots. Several synthetic peptides derived from predicted loop 2 and loop 5 of X-73 OmpH were synthesized as vaccine candidates. Vaccination studies in chickens showed that the cyclic synthetic peptide (Cyclic-L2) mimicking the predicted loop 2 induced 70% protection in chickens against strain X-73 challenge. This is the first report that a synthetic peptide mimicking the conformational epitopes of a native protein provide practical protection in target animal against bacterial infection.

Evaluation of a system to identify relevant patient information and its impact on clinical information retrieval

Concept-oriented views of electronic medical records are desirable, yet difficult to create. We have developed a system that creates concept-oriented views by identifying relevant patient information, however, previous such systems have received little evaluation. We present here an evaluation of our system's ability to identify relevant patient data and generate concept-oriented views, along with the clinical impact of the generated views. The evaluation was carried out in three parts: First, using physicians and medical literature as gold standards, the system's sensitivity and specificity in identifying relevant information were measured. In some areas, the system demonstrated sensitivity comparable to that of physicians. Second, concept-oriented views were compared with original records and shown to contain significantly less non-specific information. Third, physician volunteers, when answering questions about patient cases using the concept-oriented views and traditional source-oriented views generated by the system, showed a significantly greater accuracy in information retrieval using concept-oriented views.

[The permeability of the cell membrane in the human uterine smooth muscle at term pregnancy]

OBJECTIVE

To study the changes of the permeability of the uterine smooth muscle cell membrane at the various stages of labor, and comparing with the onset of labor.

METHODS

18 women (38 to 41 gestational weeks) were divided into three groups: late pregnancy not in labor, prelabor, active labor, and six cases in each group. The myometrium tissues in the corpus and lower segment of the uterus were studied by the Lanthanum tracing method under transmission electron microscopy (TEM).

RESULTS

Lanthanum entered into the smooth muscle cells, deposited in the mitochondria. The positive rates of the smooth muscle cells of lower segment by lanthanum tracing were markedly higher than that of corpus in late pregnancy group (P < 0.05), the difference were not found between lower segment and corpus in prelabor group (P > 0.05). The positive rates in corpus were significant higher than that of lower site in the active labor group (P < 0.05); Comparing corpus to corpus, the positive rates were not significantly different between late pregnancy and prelabor group (P > 0.05), then in active labor group it were markedly higher than those in the other two groups (P < 0.05, respectively); but in lower segment, the positive rates in late pregnancy group were significant higher than that in prelabor and active labor group (P < 0.05 respectively), no difference was found between prelabor and active labor (P > 0.05). The lanthanum deposition in the late pregnancy and prelabor groups was mainly showed in larger mitochondria within the smooth muscle cell while in active labor group, it laid on the outer and inner membrane and cristae of all the mitochondria.

CONCLUSION

The permeability of uterine smooth muscle cell membrane at term, pregnancy increases, especiany in uterine corpus, which showed a close correlation with the onset of labor.

[A clinicopathological immunohistochemical and cytomorphometric study on midline T cell lymphoma]

One hundred and twenty-two cases of midline malignant reticulosis (MMR) were studied. A series of antibodies including anti-LCA, UCHL-1, L26, CD45R, and anti-lysozyme were used on paraffin sections by ABC and PAP methods. The results were as follows: 112 cases exhibiting T-cell origin, 4 cases showing B-cell origin, and 6 cases being of uncertain lineage. This result is in accordance with the point of view that most of MMR are T cell lymphoma. Two histological types were classified: sarcomatoid type and granulomatoid type. By using image analyzer, the sarcomatoid type was subdivided into small, medium and large cell types. Sixty-two cases with follow-up data were collected for clinicopathologic analysis. One-year and five-year survival rates in cases with different histologic types were compared and statistically analysed. The results showed that the prognosis was closely related to the histological type.

Topoisomerase II-mediated site-directed alkylation of DNA by psorospermin and its use in mapping other topoisomerase II poison binding sites

Psorospermin is a plant natural product that shows significant in vivo activity against P388 mouse leukemia. The molecular basis for this selectivity is unknown, although psorospermin has been demonstrated to intercalate into DNA and alkylate N7 of guanine. Significantly, the alkylation reactivity of psorospermin at specific sites on DNA increased 25-fold in the presence of topoisomerase II. In addition, psorospermin trapped the topoisomerase II-cleaved complex formation at the same site. These results imply that the efficacy of psorospermin is related to its interaction with the topoisomerase II-DNA complex. Because thermal treatment of (N7 guanine)-DNA adducts leads to DNA strand breakage, we were able to determine the site of alkylation of psorospermin within the topoisomerase II gate site and infer that intercalation takes place at the gate site between base pairs at the +1 and +2 positions. These results provide not only additional mechanistic information on the mode of action of the anticancer agent psorospermin but also structural insights into the design of an additional class of topoisomerase II poisons. Because the alkylation site for psorospermin in the presence of topoisomerase II can be assigned unambiguously and the intercalation site inferred, this drug is a useful probe for other topoisomerase poisons where the sites for interaction are less well defined.

The core metal-recognition domain of MerR

MerR, the metalloregulatory protein of the mercury-resistance operon (mer) has unusually high affinity and specificity for ionic mercury, Hg(II). Prior genetic and biochemical evidence suggested that the protein has a structure consisting of an N-terminal DNA binding domain, a C-terminal Hg(II)-binding domain, and an intervening region involved with communication between these two domains. We have characterized a series of MerR deletion mutants and found that as little as 30% of the protein (residues 80-128) forms a stable dimer and retains high affinity for Hg(II). Biophysical measures indicate that this minimal Hg(II)-binding domain assumes the structural characteristics of the wild-type full-length protein both in the Hg(II) center itself and in an immediately adjacent helical protein domain. Our observations are consistent with the core Hg(II)-binding domain of the MerR dimer being constituted by a pair of antiparallel helices (possibly in a coiled-coil conformation) comprised of residues cysteine 82 through cysteine 117 from each monomer followed by a flexible loop through residue cysteine 126. These antiparallel helices would have a potential Hg(II)-binding site at each end. However, just as in the full-length protein, only one of these potential binding sites in the deleted proteins actually binds Hg(II).

Design of new topoisomerase II inhibitors based upon a quinobenzoxazine self-assembly model

A new class of pyridobenzophenoxazine compounds has been developed as topoisomerase II inhibitors for anticancer chemotherapy. These compounds were designed based on a proposed model of a quinobenzoxazine self-assembly complex on DNA. They showed excellent inhibitory effects on several tumor cell lines with nanomolar IC50 values. Their cytotoxic potency correlates with their ability to unwind DNA and inhibit topoisomerase II.

Requirement of Stat3 but not Stat1 activation for epidermal growth factor receptor- mediated cell growth In vitro

Stimulation of epidermal growth factor receptor (EGFR) by ligand(s) leads to activation of signaling molecules including Stat1 and Stat3, two members of the signal transducers and activators of transcription (STAT) protein family. Activation of Stat1 and Stat3 was constitutive in transformed squamous epithelial cells, which produce elevated levels of TGF-alpha, and was enhanced by the addition of exogenous TGF-alpha. Targeting of Stat3 using antisense oligonucleotides directed against the translation initiation site, resulted in significant growth inhibition. In addition, cells stably transfected with dominant negative mutant Stat3 constructs failed to proliferate in vitro. In contrast, targeting of Stat1 using either antisense or dominant-negative strategies had no effect on cell growth. Thus, TGF-alpha/EGFR-mediated autocrine growth of transformed epithelial cells is dependent on activation of Stat3 but not Stat1.

[Clinical and experimental study on treatment of acute alcohol intoxication with xiangnaojing injection]

OBJECTIVE

To study the therapeutical mechanism of traditional Chinese medicine Xingnaojing injection (XNJI) for acute alcohol intoxication.

METHODS

XNJI was used in treating the experimental model rabbits (n = 26) and the patients (n = 8) admitted to the emergency department with acute alcoholism. Before and after the treatment, beta-EP, superoxide anion (free radicals) and SOD were measured.

RESULTS

XNJI could enhance the regaining consciousness of rabbits and patients, simultaneously reduce the concentration of beta-EP in plasma to the normal level (drunk rabbits 127.09 +/- 13.67 ng/L, normal rabbits 41.48 +/- 7.46 ng/L. P < 0.01, drunk patients 292.97 +/- 14.85 ng/L, normal people 221.60 +/- 15.95 ng/L, P < 0.01). The concentration change of superoxide anion (free radicals) in plasma of rabbits and patients was similar to beta-EP (drunk rabbits 313.39 +/- 15.64 u/L, normal rabbits 254.27 +/- 21.71 u/L, P < 0.01; drunk patients 278.47 +/- 11.48 u/L, normal people 159.92 +/- 11.51 u/L, P < 0.01), and SOD was inversely changed (drunk rabbits 53.57 +/- 6.48%, normal rabbits 77.18 +/- 7.89%, P < 0.01; drunk patients 43.76 +/- 7.84%, normal people 82.53 +/- 4.33%, P < 0.01).

CONCLUSIONS

XNJI is similar to Naloxone in pharmacologic action. And it is an effective antioxidant. It can be used for treating alcoholism.

A novel synaptobrevin/VAMP homologous protein (VAMP5) is increased during in vitro myogenesis and present in the plasma membrane

cDNA clones encoding a novel protein (VAMP5) homologous to synaptobrevins/VAMPs are detected during database searches. The predicted 102-amino acid VAMP5 harbors a 23-residue hydrophobic region near the carboxyl terminus and exhibits an overall amino acid identity of 33% with synaptobrevin/VAMP1 and 2 and cellubrevin. Northern blot analysis reveals that the mRNA for VAMP5 is preferentially expressed in the skeletal muscle and heart, whereas significantly lower levels are detected in several other tissues but not in the brain. During in vitro differentiation (myogenesis) of C2C12 myoblasts into myotubes, the mRNA level for VAMP5 is increased approximately 8- to 10-fold. Immunoblot analysis using antibodies specific for VAMP5 shows that the protein levels are also elevated approximately 6-fold during in vitro myogenesis of C2C12 cells. Indirect immunofluorescence microscopy and immunoelectron microscopy reveal that VAMP5 is associated with the plasma membrane as well as intracellular perinuclear and peripheral vesicular structures of myotubes. Epitope-tagged versions of VAMP5 are similarly targeted to the plasma membrane.

Normalization of EGFR mRNA levels following restoration of wild-type p53 in a head and neck squamous cell carcinoma cell line

Head and neck squamous cell carcinoma (HNSCC) is frequently characterized by mutation of the p53 tumor suppressor gene and increased expression of the epidermal growth factor receptor (EGFR). To determine the potential link between p53 and EGFR expression, we examined the effect of overexpressing wild-type p53 on EGFR mRNA levels in HNSCC. In these studies, a temperature-sensitive (ts) p53 mutant was transfected into an HNSCC line which contained a deletion of one allele of the p53 gene and a mutation of the remaining allele. Following selection, six clones were isolated, characterized by Southern blot analysis, and stable expression of mutant p53 protein was confirmed by immunoblotting of clones grown at the mutant temperature. Total RNA was isolated from transfectants grown at both wild-type or mutant temperatures followed by Northern blot analysis to determine levels of EGFR mRNA expression at the two p53 conformations. Clones grown at the wild-type temperature (32.5 degreesC) demonstrated a 69% 13% decrease in EGFR mRNA compared with the same cells grown at the mutant temperature (39.5 degreesC; p=0.006) indicating that restoration of wild-type p53 reduces EGFR mRNA levels in this HNSCC cell line. These findings suggest that abnormalities in p53 may contribute to activation of EGFR gene transcription.

Inhibition of human squamous cell carcinoma growth in vivo by epidermal growth factor receptor antisense RNA transcribed from the U6 promoter

BACKGROUND

Squamous cell carcinomas of the head and neck (SCCHN), unlike normal mucosal squamous epithelial cells, overexpress epidermal growth factor receptor (EGFR) messenger RNA and protein. EGFR protein is required to sustain the proliferation of SCCHN cells in vitro. To determine whether EGFR expression contributes to tumor growth, we investigated the effect of suppressing EGFR expression in tumor xenografts through in situ expression of antisense oligonucleotides.

METHODS

Intratumoral cationic liposome-mediated gene transfer was used to deliver plasmids capable of expressing sense or antisense EGFR sequences into human head and neck tumors, which were grown as subcutaneous xenografts in nude mice. The oligonucleotides were expressed under the control of the U6 RNA promoter.

RESULTS

Direct inoculation of the EGFR antisense (but not the corresponding sense) plasmid construct into established SCCHN xenografts resulted in inhibition of tumor growth, suppression of EGFR protein expression, and an increased rate of apoptosis (programmed cell death). Sustained antitumor effects were observed for up to 2 weeks after the treatments were discontinued.

CONCLUSION

These results suggest that interference with EGFR expression, using an antisense-based gene therapy approach, may be an effective means of treating EGFR-overexpressing tumors, including SCCHN.

A single plasmid vector (pSTAR) mediating efficient tetracycline-induced gene expression

A plasmid vector (pSTAR) has been constructed which confers neomycin resistance for selecting stably transfected cells, possesses a cloning cassette for placing a gene of interest under the control of the tetO DNA motif, and expresses rtTAnls which, upon association with tetracycline, binds to and drives gene expression from the tetO DNA motif. The plasmid pSTAR/LacZ, which has the gene for beta-galactosidase inserted into the cloning cassette, was transfected into Chinese hamster ovary (CHO) cells and selected for stably transfected cells. In pooled transfectants of CHO, tetracycline induced the expression of beta-galactosidase in 10-30% of cells. Using clonal transfectants, beta-galactosidase expression was induced by tetracycline in essentially every cell. Furthermore, induction of beta-galactosidase expression by tetracycline was both dose- and time-dependent. Similar tetracycline-induced beta-galactosidase expression is also observed in other cell types. The pSTAR vector is thus suited to facilitate the application of tetracycline-induced gene expression in diverse research areas.

Immunoreactive endothelin-1 and its receptors in human adrenal tissues

To elucidate the pathophysiologic significance of endothelin-1 (ET-1) in adrenal and the mechanism for reduced responsiveness to exogenous ET-1 in aldosterone-producing adenoma (APA), we have investigated ET-1 receptors by radioligand binding assay (RBA) in human normal adrenal (NA), APA, idiopathic hyperaldosteronism (IHA), and pheochromocytoma (PHEO), immunoreactive (ir-) ET-1 content in NA, APA and PHEO by radioimmunoassay (RIA), and immunohistochemical staining of ET-1 with the peroxidase-anti-peroxidase (PAP) method in NA, APA, and PHEO. A single class of high-affinity binding sites for ET-1 was found in human NA and tumor tissues. Dissociation constant (Kd) values of ET-1 receptors were similar in NA, APA, and IHA, but maximal binding capacity (Bmax) of ET-1 receptors was lower in APA than in NA and IHA. Both Kd and Bmax in PHEO were higher than those in NA, APA, and IHA. Ir-ET-1 content in tumors of APA and PHEO were higher than in NA. Immunohistochemical staining was more intense in the tumor cells of APA and PHEO than in NA. These results suggest that the reduced response to exogenous ET-1 in APA could be related to downregulation of ET-1 receptors in the tumor. Increased ET-1 content and receptors may lead to hypersecretion of catecholamine in PHEO. ET-1 produced in normal and tumor adrenal tissues may regulate aldosterone and catecholamine secretion from adrenals in a paracrine/autocrine fashion.

[Cytotoxic effect of mitomycin C on the nonpigmented epithelium of ciliary body in rabbit eyes]

OBJECTIVE

To observe pathomorphological changes of nonpigmented epithelial cells (NECs) of ciliary body after local single application of mitomycin C (MMC) during sclerectomy in rabbit eyes, and to explore cytotoxic effect of MMC on ciliary body.

METHODS

A single five minutes intraoperative exposure to the agent MMC (0.2 mg/ml, 0.1 ml) was used during sclerectomy in rabbit eyes. The treated area was rinsed with 20 ml normal saline. The NECs of ciliary body at the operated area were observed under light microscope and transmission electron microscope on the 7th and 28th day postoperatively.

RESULTS

On the 7th day postoperatively, the NECs were swollen, and the intracellular abundant mitochondria were swollen and vacuolized. String pearls-like membrane-encapsulated vacuoles were present in the intervals of beta-cell membrane of the NECs. On the 28th day postoperatively, these damages were gradually recovered.

CONCLUSIONS

These findings suggest a toxic effect of MMC on the NECs of ciliary body, possibly that can decrease the aqueous production and intraocular pressure, even causing persistent hypotony.

[Morphometric analysis of gap junctions of the cell membrane in human uterine smooth muscle at term]

OBJECTIVE

To study the changes of the gap junctions (GJS) in the uterine smooth muscle cells at various stages of labor, and its relationship with the onset of labor.

METHODS

18 women (38 to 41 gestational weeks) were divided into three groups: not-in-labor, pre-labor, active in labor and six cases in each group. The uterine myometrium tissues were observed by transmission electron microscopy (TEM) and lanthanum tracing method.

RESULTS

The lengths and areas of GJS in uterine corpus and lower segment in the active in labor group were significantly larger than that of the other 2 groups, but there was no significant difference between the not-in-labor and pre-labor groups. The area but not the lengths of GJS in corpus was significant larger than that in the lower segment in the active in labor group.

CONCLUSION

The great increase of length and areas of GJS in all parts of the uterine smooth muscle was closely correlated with onset of labor.

Downmodulation of TGF-alpha protein expression with antisense oligonucleotides inhibits proliferation of head and neck squamous carcinoma but not normal mucosal epithelial cells

Interruption of an autocrine growth pathway involving TGF-alpha and EGFR may inhibit tumor growth and improve survival in head and neck cancer patients. We previously demonstrated that biopsy specimens and established cell lines from patients with squamous cell carcinoma of the head and neck (SCCHN) overexpress TGF-alpha and its receptor, epidermal growth factor receptor (EGFR) at both the mRNA and protein levels. Protein localization studies showed that TGF-alpha and EGFR are produced by the same epithelial cells in tissues from head and neck cancer patients further supporting a role for this ligand-receptor pair in an autocrine growth pathway. To confirm that TGF-alpha contributes to autocrine growth, we examined the effect of down regulation of TGF-alpha protein on SCCHN cell proliferation. Treatment of 6 SCCHN cell lines with antisense oligodeoxynucleotides targeting the translation start site of human TGF-alpha mRNA decreased TGF-alpha protein production by up to 93% and reduced cell proliferation by a mean of 76.2% compared to a 9.7% reduction with sense oligonucleotide (range P = 0.036-0.0001). TGF-alpha antisense oligonucleotide exposure also decreased TGF-alpha protein levels in normal oropharyngeal mucosal epithelial cells, however their growth rate was not affected. These findings indicate that TGF-alpha is participating in an autocrine signaling pathway in transformed, but not in normal mucosal epithelial cells, that promotes proliferation.

Mouse PRL-2 and PRL-3, two potentially prenylated protein tyrosine phosphatases homologous to PRL-1

Protein tyrosine phosphatases (PTPs) play a fundamental role in regulating diverse cellular processes. PRL-1 is a unique nuclear PTP that is induced in mitogen-stimulated cells and regenerating liver. Database searches using the PRL-1 sequence led to the identification of mouse PRL-2 and PRL-3 which exhibit 87% and 76% identity to mouse PRL-1 in their amino acid sequences. All three mouse PRL proteins contain a C-terminal consensus sequence for prenylation. All PRL proteins bear significant sequence homology to Cdc14p and the recently identified tumor suppressor PTEN/MMAC1, in regions other than the conserved PTP signature motif. The nucleotide sequences of the coding regions of mouse PRL-2 and PRL-3 are, respectively, 71% and 62%, identical to mouse PRL-1, while the 5' un-translated regions of mouse PRL-1, PRL-2, and PRL-3 are much more divergent. Northern blot analysis revealed that PRL-2 is preferentially expressed in skeletal muscle, while PRL-3 is preferentially expressed in both skeletal muscle and heart, although both PRL-2 and PRL-3 are expressed at lower levels in other tissues.

The change of arteriovenous carbon dioxide and pH gradients during severe hemorrhagic shock and resuscitation

OBJECTIVE

To investigate clinically useful markers for determining the severity of hemorrhagic shock and adequacy of resuscitation.

METHODS

Prospective study was undertaken in 12 dogs, using an established model for hemorrhagic shock. The anesthetized dogs were bled to a mean arterial pressure of 40 mmHg which was maintained for 3 hours. Then each animal was resuscitated with heperinized whole blood followed by intravenous infusion of dobutamine at a rate of 5 micrograms.kg-1.min-1 for 10 minutes. Arterial and mixed venous blood gases, arterial lactate concentrations and hemodynamic parameters were measured throughout the study.

RESULTS

A difference in the PCO2 and pH values between arterial and mixed venous blood was observed. Arterial-venous PCO2 and pH difference increased significantly after sustained shock. The arteriovenous carbon dioxide and pH gradients recovered more rapidly than arterial lactate levels after successful resuscitation with blood and dobutamine.

CONCLUSION

Arterial blood gases fail to reflect the acid-base status of tissues during hemorrhagic shock. The differences in PCO2 and pH values between arterial and mixed venous blood could be used as clinical indicators for assessing the severity of shock and efficacy of resuscitation.