[Determination of Ni in biological samples with graphite furnace atomic absorption spectrometpy]

In this paper, Ni was determined in biological samples such as blood, serum and urine by HGAAS. This method was simple, rapid, good precision and high accuracy. The sensitivity of blood, serum and urine is 0.48 microgram.L1, 0.24 microgram.L1, 0.50 microgram.L1. The relative standard deviation is 2.9-5.4% and the recovery is 71-103%.

Diffusion measurements in intracranial hematomas: implications for MR imaging of acute stroke

BACKGROUND AND PURPOSE

The purpose of our study was to analyze the diffusion properties of intracranial hematomas to understand the effects of hematomas on diffusion-weighted MR images of patients with acute stroke and to further our understanding of the evolution of signal intensities of hematomas on conventional MR images. We hypothesized that hematomas containing blood with intact RBC membranes (ie, early hematomas) have restricted diffusion compared with hematomas in which RBC membranes have lysed.

METHODS

Seventeen proven intracranial hematomas were studied with conventional and diffusion MR imaging. Hematomas were characterized using conventional images to determine the stage of evolution and their putative biophysical composition, as described in the literature. Apparent diffusion coefficient (ADC) measurements for each putative hematoma constituent (intracellular oxyhemoglobin, intracellular deoxyhemoglobin, intracellular methemoglobin, and extracellular methemoglobin) were compared with each other and with normal white matter.

RESULTS

Hematomas showing hemoglobin within intact RBCs by conventional MR criteria (n = 14) showed equivalent ADC values, which were reduced compared with hematomas containing lysed RBCs (P = .0029 to .024). Compared with white matter, hematomas containing lysed RBCs had higher ADC measurements (P = .003), whereas hematomas containing intact RBCs had reduced ADC measurements (P < .0001).

CONCLUSION

Restricted diffusion is present in early intracranial hematomas in comparison with both late hematomas and normal white matter. Therefore, early hematomas would be displayed as identical to the signal intensity of acute infarction on ADC maps, despite obvious differences on conventional MR images. These data also are consistent with the biochemical composition that has been theorized in the stages of evolving intracranial hematomas and provide further evidence that paramagnetic effects, rather than restriction of water movement, are the dominant cause for their different intensity patterns on conventional MR images.

[Preparation of monoclonal antibodies against malaria through immunization of mice with recombinant plasmid DNA]

BALB/c mice were immunized by injection of recombinant plasmid DNA carrying MSP1-31 fragment of Plasmodium falciparum. After antiserum was induced, McAbs were prepared by fusing SP2/0 myeloma cells with spleen cells. Specific McAbs were detected in hybridoma culture supernatant and mouse ascites by ELISA, positive hybridomas were cloned by technique of limiting dilutions. Two McAbs, 9H9 and 8A2, against the malaria protein were produced and characterized. The titers of the two McAbs in acites were 1:10,000 and 1:2500 respectively. The Ig subclass of these McAbs was IgG1. Western blot test showed that the McAb specifically reacted with MSP1-31 antigen. These results proved that monoclonal antibodies could be produced by use of immunization of mice with plasmid DNA or DNA vaccine.

Identification of the residues in the extracellular region of KDR important for interaction with vascular endothelial growth factor and neutralizing anti-KDR antibodies

The kinase domain receptor (KDR) of vascular endothelial growth factor (VEGF) is the main human receptor responsible for the angiogenic activity of VEGF. The extracellular region of KDR is comprised of seven immunoglobulin-like domains, of which the first three have been shown to be required for ligand binding. We have previously described antibodies directed against the extracellular region of KDR, including MAB383 and MAB664, which were shown to block the binding of VEGF to the receptor and to inhibit both VEGF-induced mitogenesis of human endothelial cells in vitro and tumor growth in vivo. Here we generated a series of KDR deletion mutants consisting of truncated extracellular regions and mapped out the domain(s) responsible for binding to VEGF and the neutralizing anti-KDR antibodies. All neutralizing antibodies were found to require domain 3 for efficient binding. Alanine-scanning mutagenesis of domain 3 identified two different sets of five residues, Ile(256), Asp(257), Glu(261), Leu(313), and Thr(315) and Tyr(262), Pro(263), Ser(264), Ser(265), and Lys(266), that were critical for binding to MAB383 and MAB664, respectively. Combination of alanine mutations affecting both MAB383 and MAB664 binding resulted in a variant that also lost binding to VEGF. These results suggest that the residues within this region of domain 3 are critical for VEGF binding. Our studies provide a basis for the mechanism of action of our anti-KDR antibodies and establish a functional foundation for the development of other classes of antagonists to the receptor.

The effect of transient balloon occlusion of the mitral valve on left atrial appendage blood flow velocity and spontaneous echo contrast: a comparison in sinus rhythm and atrial fibrillation patients

OBJECTIVE

To investigate the relationship between spontaneous echo contrast (SEC) and left atrial appendage (LAA) blood flow velocity using transesophageal echocardiography (TEE) during percutaneous balloon mitral valvotomy (PBMV) in patients with atrial fibrillation and sinus rhythm.

METHODS

Thirty-five patients (21 in sinus rhythm and 14 in atrial fibrillation) with rheumatic mitral stenosis underwent PBMV with intraoperative transesophageal echocardiography monitoring. We measured LAA blood flow velocities and observed the left atrium for various grades of SEC (from 0 = none to 4 = severe), before and after each balloon inflation.

RESULTS

Left atrial appendage maximal emptying velocity (LAA MEV) was reduced from 35 +/- 14 cm/s to 6 +/- 2 cm/s at peak balloon inflation and increased to 40 +/- 16 cm/s after balloon deflation. Comparison of the values before balloon inflation and after balloon deflation showed that LAA velocities were significantly lower (P < 0.001). During balloon inflation, both maximal emptying velocity (MEV) and maximal filling velocity (MFV) were significantly decreased, compared to those before inflation and after balloon deflation (P < 0.01). And both MEV and MFV were significantly higher after balloon deflation relative to those before balloon inflation. Patients with atrial fibrillation had significantly lower MEV and MFV before and during balloon inflation and after balloon deflation than patients with sinus rhythm. At peak balloon inflation, new or increased SEC grades were observed during 54 of 61 (88%) inflations and unchanged during 7 (12%) inflations. SEC grades were reduced after 55 balloon deflations (90%), completely disappeared after 18 deflations (30%) and remained unchanged after 6 deflations (10%). At peak balloon inflation, left atrium spontaneous echo contrast (LASEC) grade 4 was observed during 14 of 27 (93%) inflations in the atrial fibrillation patients, significantly higher than in patients with sinus rhythm (8 of 34, 24%; P < 0.05). LASEC completely disappeared after 16 of 34 deflations (47%) in the patients with sinus rhythm, significantly higher than in the atrial fibrillation patients (2 of 27 deflations; P < 0.01). The mean time to achieve maximal SEC grade (2.5 +/- 1.2 s) correlated with the mean time to trough LAA velocities (2.3 +/- 1.1 s) after balloon inflation. Both the time to lowest LAA velocity and the time to highest LASEC were significantly longer in the patients with sinus rhythm than in the atrial fibrillation patients (2.6 +/- 1.1 s vs 1.7 +/- 1.0 s, P < 0.05 and 2.8 +/- 1.4 s vs 1.9 +/- 1.3 s, P < 0.05, respectively). Upon deflation, the mean time to lowest SEC grade (2.9 +/- 1.8 s) correlated with the mean time to achieve maximal LAA velocities (2.7 +/- 1.6 s). Both intervals are significantly shorter in the patients with sinus rhythm than in the atrial fibrillation patients (2.0 +/- 1.6 s vs 3.5 +/- 1.5 s, P < 0.01 and 2.2 +/- 1.7 s vs 3.6 +/- 1.6 s, P < 0.05).

CONCLUSION

Reducing the blood flow velocity in the human left atrium by balloon occlusion of the mitral valve may enhance SEC, whereas restoring blood flow after balloon deflation would cause enhanced echogenic blood to disappear or decrease in both groups of patients. Patients with atrial fibrillation demonstrate more severe blood stagnation of the left atrial body and appendage during transient balloon inflation at mitral valve orifice and slower recovery from the stagnation, decreasing to a lesser extent after balloon deflation, when compared to patients with sinus rhythm.

Two cases of AML (M2) with a t(8;19)(q22;q13): a new cytogenetic variant

"Simple" variants of the t(8;21) translocation involving chromosome 8 and a chromosome other than number 21 are rare. To our knowledge, only t(3;8)(q29;q22), t(8;11)(q22;q13), t(8;16)(q22;q24), t(8;20)(q22;p13), and t(8;22) have been reported in the literature. This paper describes for the first time two patients with acute myelogenous leukemia with a consistent t(8;19)(q22;q13) translocation. Their myelograms were compatible with the FAB-M2 subtype. The blasts from case 2 expressed CD34, CD33, CD13, and CD19. Karyotype analyses were performed on bone marrow cells using R- and G-banding at presentation. A t(8;19)(q22;q13) translocation was found in 28/30 metaphases for case 1 and in 23/25 metaphases for case 2. The latter case also had a deletion of chromosome 9, del(9)(q12q22) as an additional abnormality. Reverse transcriptase-polymerase chain reaction study revealed no AML1/ETO fusion transcript in case 2. Dual-color fluorescence in situ hybridization (FISH) assay using two probes (BAC92 and YAC412A4) convincingly demonstrated that the chromosomal material from 8q was translocated onto 19q rather than 19p in case 2. Thus, we consider t(8;19)(q22;q13) a true "simple" variant of t(8;21), and assume that a fusion gene resulting from the t(8;19) may contain the ETO gene located at 8q22 and an unknown partner gene from 19q13, which probably is a new transcription factor, whose molecular entity warrants further study.

Sinus histiocytosis with massive lymphadenopathy and malignant lymphoma involving the same lymph node: a report of four cases and review of the literature

Sinus histiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease, is a disorder of unknown cause. Rarely, patients with SHML also have malignant lymphoma, usually involving anatomic sites different from those involved by SHML We report four patients in whom SHML and malignant lymphoma were identified in the same lymph node biopsy specimen. The SHML in each case was present as a small focus, less than 1 cm. Immunohistochemical studies showed that the abnormal histiocytes were positive for S-100 and negative for CD1a. The malignant lymphomas included two cases of follicular lymphoma and two cases of Hodgkin's disease, nodular lymphocyte predominant type. The presence of SHML in these patients did not impact clinical decisions, and there was no evidence of SHML elsewhere. Thus, the presence of focal SHML associated with malignant lymphoma in these cases was an incidental histologic finding that seems not to have had any clinical significance.

[The analysis of the changes of tongue shape and position, hyoid position in Class II, division 1 malocclusion treated with functional appliances (FR-I)]

OBJECTIVE

The objective of this study is to analyze the changes of tongue shape and position, hyoid position with FR-I therapy in class II, division 1 malocclusion.

METHODS

12 patients with class II, division 1 malocclusion treated with FR-I appliance(8 male, 4 female, average 11 years old) were chosen. The acceptable standard of this experiment was an horizontal growth pattern with normal maxilla, retracted mandible and short lower facial height. The average period of treatment was about 8 months. The assessment was made from a lateral cephalogram taken in habitual occlusion before and after treatment. The shapes and sizes of tongue can be measured from the occlusal films with template. These seven lines from six angles of 30 degrees which can be marked in millimeter. Fig 2 showed the reference points and lines: Is1 (the incisal margin of the lower incisors), Mc (the tip of the distobuccal cusp of the lower fist molar), V(the most caudal point on the shadow of the soft palate or its projection onto the reference line). Is1 connected Mc by a straight line extended to V to form the reference lines. After the lines were constructed, the middle point between Is1 and V was called O, and a perpendicular line was constructed from it to the palate contour. The baseline of the template was coincided with the constructed reference line, and the vertical line intersected the reference line at O. The template was placed over the constructed lines, and the exact measurements of the root, the dorsum and the tip of tongue were taken. This was done along the seven constructed lines, and the measurement gived a relative size of the tongue(e.g. the size related to the oral cavity).

RESULTS

After treatment, the shape of tongue changed as a result of the increase of oral cavity. There was a tendency that the position of the tongue shifted forwarded and the tip of tongue lied further forward. At the same time, the position of hyoid moved forward in a horizontal dimension and downward in a vertical dimension.

CONCLUSION

It confirms that the therapeutic mechanism of FR-I is to induce an anterior shift of mandible and lead to a forward position of tongue, hyoid and cervical soft tissue, which modify the saggital relationship of jaws. The shape of tongue changes due to the increase of oral cavity.

[Cytogenetics and clinical studies of hematologic malignancies with 11q23 abnormalities in China]

OBJECTIVE

To evaluate the association between 11q23 abnormalities and the clinical, hematologic, prognostic aspects of hematologic malignancies.

METHODS

A total of 6000 cases of hematologic malignancies from our hospital and near regions in China were investigated between October 1985 and November 1998. Chromosome preparations were made on bone marrow cells by using direct method and/or unstimulated short-term cultures. Karyotypes were analyzed by R-banding technique and expressed according to ISCN(1995).

RESULTS

11q23 abnormalities were found in 28 of 6000 cases with hematologic malignancies(0.47%). It may be separated into seven cytonetic categories: t(4;11)(q21;q23)(ten cases), t(11;19)(q23;p13)(five cases), t(9;11)(p12;q23)(two cases), t(10;11)(p15;q23)(two cases), t(6;11)(q27;q23) (one case), del(11)(q23)(seven cases), and t(11;?)(q23;?)(one case). The diagnoses included acute myeloid leukemia in 14 cases (M(2a), three; M(4), two; M(5a), one; M(5b), eight), acute lymphoblastic leukemia(ALL) in 10 cases, myelodysplastic syndrome in three cases and malignant histiocytosis in one case. All 10 cases with t(4;11) anomaly were ALL. Follow-up data were available for 22 of them. Their median survival was 113 days. The patients may be grouped according to the presence or absence of additional abnormalities and/or normal karyotype. The median survival was 75 days for five patients with 11q23 anomaly only, 18 days for two patients with 11q23 and additional abnormalities, 135 days for 10 patients with 11q23 anomaly, additional abnormalities and normal karyotype, and 150 days for 5 patients with 11q23 anomaly and normal karyotype.

CONCLUSION

11q23 abnormalities were mainly seen in ALL and acute monocytic leukemia. Their prognosis was very poor. Both additional abnormalities and lack of normal karyotype had adverse effects on the survival of patients. Thus, they represent a unique clinical-cytogenetic association. 11q23 abnormality; hematologic malignancy; acute monocytic leukemia; acute lymphoblastic leukemia; prognosis

Multiple origins of Tibetan Y chromosomes

The genetic origin of Tibetans was investigated using Y chromosome markers. A total of three populations were studied, two from central Tibet speaking central Tibetan and one from Yunnan speaking Kham. Two dominant paternal lineages (>80%) were identified in all three populations with one possibly from central Asia (YAP+) and the other from east Asia (M122C). We conclude that Tibetan Y chromosomes may have been derived from two different gene pools, given the virtual absence of M122C in central Asia and YAP+ in east Asia, with drift an unlikely mechanism accounting for these observations.

[Relationship between human herpesvirus 6 infection and idiopathic thrombocytopenic purpura]

OBJECTIVE

To investigate the pathogenic role of human herpesvirus 6 (HHV-6) in idiopathic thrombocytopenic purpura (ITP).

METHODS

HHV-6 DNA was examined by polymerase chain reaction (PCR) in bone marrow mononuclear cells (BMMNC) of 105 ITP patients. Human cytomegalovirus (HCMV) and parvovirus B(19) DNA were also examined in some cases. Platelet-associated antibodies (PAIg) were measured by competitive ELISA in 66 ITP patients. Serum IgG titer to HHV-6 was observed by indirect immunofluorescence assay in 19 ITP patients.

RESULTS

(1) HHV-6 DNA positivity was 41.0% for ITP patients, significantly higher than that for control group (P < 0.05). HHV-6 DNA positivity for adult ITP patients, especially adult chronic cases was significantly higher than that for childhood patients (P < 0.025). Positivities for parvovirus B(19) and HCMV DNA were 24.1% and 9.7%, respectively. (2) HHV-6 DNA positivity for patients with abnormal level of PAIgG was significantly higher than that for patients with normal level of PAIgG (P < 0.05). (3) Patients coinfected with HHV-6 and B(19) or HCMV had more severe symptoms or poorer prognosis.

CONCLUSION

HHV-6 infection might be associated with excessive PAIgG. Coinfection with HHV-6, B(19) or HCMV may cause more severe symptoms in ITP patients.

[Chromosome t (4; 11) acute lymphoblastic leukemia: an analysis of 10 cases]

OBJECTIVE

To characterize morphologically, immunophenotypically, cytogenetically and clinically the acute lymphoblastic leukemia (ALL) with t (4; 11) (q21; q23).

METHODS

Ten cases of t (4; 11) ALL were reported. Of them, eight patients were de novo and two relapsed. The patients were treated with combination chemotherapy of DOPL or VP regimen. Immunophenotypic analysis was performed by flow cytometry in seven cases. Cytogenetic analysis was performed using bone marrow cells prepared directly and/or after 24h culture (case 7 using peripheral blood). RHG banding was used for karyotypic analysis.

RESULTS

Ten (3.5%) of 285 ALL patients were found to be t (4; 11) ALL. In these 10 patients, increased WBC (> 100 x 10(9)/L) was found in 6 cases. Liver, spleen and/or lymph nodes were involved in all. t (4; 11) was detected as a single abnormality in 5 karyotypes whereas the other 5 showed additional aberration besides t (4; 11). Six patients were CD(19) (+), five were CD(22) (+) and one was HLA-DR (+), CD(5) (+), supporting that most cases of t (4; 11) ALL were B cell origin. Median survival time was 5.5 months in the present series.

CONCLUSION

t (4; 11) ALL was a subtype with unique clinical and cytogenetic features, and had a poor prognosis.

[Acute myeloid leukemia M2and t (8; 19) (q22; q13)]

OBJECTIVE

Report for the first time of two cases of acute myeloid leukemia (AML) M(2) with t (8; 19) (q22; q13).

METHODS

Chromosome specimens were prepared by short-term culture of bone marrow cells and karyotype analyses were carried out using R-and G-banding techniques. Immunophenotyping of the blast cells was analyzed by flow cytometry with a panel of monoclonal antibodies. AML1/ETO fusion gene was tested by "nested" reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Karyotype analyses showed 46, XX, t (8; 19) (q22; q13) [28]/46, XX [2] in case 1 and t (8; 19) (q22; q13), del (9) (q12q22) [23]/46, XY [2] in case 2. In case 2, the blast cells expressed CD(13) (38.8%), CD(33) (31.8%), CD(34) (80.9%), and CD(19) (63.9%) and RT-PCR assay revealed no AML1/ETO fusion gene transcript.

CONCLUSION

t (8; 19) (q22; q13) is a variant form of t (8; 21) (q22; q22). Its molecular entity remains to be elucidate.

Activation of recombinant proenteropeptidase by duodenase

Duodenase, a serine proteinase from bovine Brunner's (duodenal) glands that was predicted to be a natural activator of enteropeptidase zymogen, cleaves and activates recombinant single-chain bovine proenteropeptidase (kcat/Km = 2700 M(-1) s(-1)). The measured rate of proenteropeptidase cleavage by duodenase was about 70-fold lower compared with the rate of trypsin-mediated cleavage of the zymogen. The role of duodenase is supposed to be the primary activator of proenteropeptidase maintaining a certain level of active enteropeptidase in the duodenum. A new scheme of proteolytic activation cascade of digestive proteases is discussed.

Third-frequency-moment sum rule for electronic multilayers

The authors establish the third-frequency-moment sum rules for the density-density reponse matrix of electronic multilayer structures modeled as an array of N parallel two-dimensional (2D) electron-plasma monolayers. Layer densities and spacings between adjacent layers need not be equal. Contact is made with previously established sum rules for the isolated 2D electron liquid and type-1 infinite superlattices. The case of the equal-density bilayer is considered and its third frequency-moment-sum-rules for the in-phase and out-of-phase inverse dielectric functions are formulated.

Cerebral microvascular obstruction by fibrin is associated with upregulation of PAI-1 acutely after onset of focal embolic ischemia in rats

The mechanisms underlying cerebral microvascular perfusion deficit resulting from occlusion of the middle cerebral artery (MCA) require elucidation. We, therefore, tested the hypothesis that intravascular fibrin deposition in situ directly obstructs cerebral microcirculation and that local changes in type 1 plasminogen activator inhibitor (PAI-1) gene expression contribute to intravascular fibrin deposition after embolic MCA occlusion. Using laser-scanning confocal microscopy (LSCM) in combination with immunofluorescent staining, we simultaneously measured in three dimensions the distribution of microvascular plasma perfusion deficit and fibrin(ogen) immunoreactivity in a rat model of focal cerebral embolic ischemia (n = 12). In addition, using in situ hybridization and immunostaining, we analyzed expression of PAI-1 in ischemic brain (n = 13). A significant (p < 0.05) reduction of cerebral microvascular plasma perfusion accompanied a significant (p < 0.05) increase of intravascular and extravascular fibrin deposition in the ischemic lesion. Microvascular plasma perfusion deficit and fibrin deposition expanded concomitantly from the subcortex to the cortex during 1 and 4 hr of embolic MCA occlusion. Three-dimensional analysis revealed that intravascular fibrin deposition directly blocks microvascular plasma perfusion. Vascular plugs contained erythrocytes, polymorphonuclear leukocytes, and platelets enmeshed in fibrin. In situ hybridization demonstrated induction of PAI-1 mRNA in vascular endothelial cells in the ischemic region at 1 hr of ischemia. PAI-1 mRNA significantly increased at 4 hr of ischemia. Immunohistochemical staining showed the same pattern of increased PAI-1 antigen in the endothelial cells. These data demonstrate, for the first time, that progressive intravascular fibrin deposition directly blocks cerebral microvascular plasma perfusion in the ischemic region during acute focal cerebral embolic ischemia, and upregulation of the PAI-1 gene in the ischemic lesion may foster fibrin deposition through suppression of fibrinolysis.

Study of thrombopoietin for gene therapy of thrombocytopenia

Thrombopoietin (TPO) is likely to he a potent, specific and reliable medication in the treatment of thrombocytopenia. A TPO-highly-expressed plasmid pcDNA3-TPO was constructed and a primary study was made on the expression of TPO cDNA in vitro and gene transfer study for thrombocytopenia in vivo. rhTPO showed complete and stable bioactivity by a series of indicators. High expression of TPO was detected in plasma from healthy mice or thrombocytopenia mice model receiving direct intramuscular injection of pcDNA3-TPO. And the platelet level of healthy mice peaked to 1.9-fold of baseline. Mice with CTX-induced thrombocytopenia achieved profound nadirs, acceleration of recovery, even 1.8-2.0-fold supranormal levels of peripheral platelet counts. The results offered experimental support for clinical application of gene therapy for thrombocytopenia via direct intramuscular injection of TPO cDNA.

An experimental investigation of osseointegration and stability of implants used as orthodontic anchorage in dogs

OBJECTIVE

To investigate osseointegration and stability of three kinds of implants used as orthodontic anchorage in dogs.

METHODS

HA-coated, titanium plasma-coated, and uncoated titanium implants were inserted into each femur of two dogs. After a healing period of three months, orthodontic force of 200 g was applied by means of Ni-Ti springs which were connected to the two adjacent implants for two months. Position change of the implant was first measured and then calculated. The shear bond strength of the interface between implant and bone was measured with a push test. After the test, the fracture surface at the interface was observed with a scanning electronic microscope.

RESULTS

All implants were stable, without mobility. The highest bond strength and mature bone compactness were found at the interface between HA-coated implant and bone. The other two showed no significant difference in bond strength. However, osseointegration existed at the interface between all three kinds of implants and bone.

CONCLUSION

HA-coated, titanium plasma-coated, and uncoated titanium implants can each serve as orthodontic anchorage as well as prosthodontic abutment.

Retrovirally mediated delivery of angiotensin II type 1 receptor antisense in vitro and in vivo

In spite of excellent drugs that are available for the control of hypertension, the pharmacological approach has major disadvantages including compliance, side effects, and inability to cure the disease. In the present chapter we provide evidence that a gene therapy concept based on the inhibition of the RAS at a genetic level, with the use of an antisense to the AT1R, is an exciting and viable approach for long-term control of hypertension without the disadvantages inherent in pharmaceutical therapy. A retrovirus-based vector has been used to deliver AT1R-AS in Ang II target tissues both in vitro and in vivo. The transduction efficiency is high and leads to the attenuation of Ang II action in vitro and prevention of hypertension in the SH rat, a model for primary human hypertension. These studies have unveiled a new avenue in which a similar approach could be attempted in the reversal of hypertension in adult animals.

Receptor tyrosine kinase tie 1 mRNA is upregulated on cerebral microvessels after embolic middle cerebral artery occlusion in rat

Tie 1 is an endothelial specific transmembrane receptor tyrosine kinase and may be required during angiogenesis. Using in situ hybridization, we measured tie 1 mRNA in ischemic brain (n=15). Rats were subjected to middle cerebral artery (MCA) occlusion by a single fibrin rich clot. Expression of tie 1 was not detected in non ischemic brain. Cerebral microvessels expressed tie 1 in the ischemic lesion as early as 2 h after MCA occlusion. The number of microvessels containing tie 1 mRNA decreased in the ischemic lesion at 8 h after MCA occlusion. However, expression of tie 1 increased on microvessels at 24 h and 14 days after ischemia and tie 1 was primarily localized to the microvessels bordering pan necrotic tissue. Ninety-seven percent of cerebral vessels which expressed tie 1 mRNA had diameters of 3.7+/-0.17 microm. Our findings suggest a role for tie 1 in cerebral microvascular remodeling after embolic stroke.

Acquired antagonistic activity of a bispecific diabody directed against two different epitopes on vascular endothelial growth factor receptor 2

Bispecific antibody (BsAb) technology has been successfully used as a means to construct novel antibody (Ab) molecules with increased avidity for binding, by combining two Ab or their fragments directed against different epitopes within the same antigen. Using two single chain antibodies (scFv) isolated from a phage display library, we have constructed a bispecific diabody directed against two different epitopes on the extracellular domain (ECD) of human vascular endothelial growth factor receptor 2 (VEGFR2), the kinase-insert domain-containing receptor (KDR). Neither of the parent scFv blocks KDR/VEGF interactions or inhibits VEGF-induced receptor activation. The diabody binds to KDR with an affinity that is 1.5- to 3-fold higher than its parent scFv, mainly due to a much slower dissociation rate (k(off)), which is approximately 17- to 26-fold slower than that of the individual scFv. In addition, the diabody binds simultaneously to, and thus cross-links, the two epitopes on the receptor(s). It is rather unexpected that the diabody effectively blocked KDR/VEGF interactions, and inhibited both VEGF-induced activation of the receptor and mitogenesis of human endothelial cells. Taken together, our results suggest that the diabody is most likely to exert its effect through steric hindrance and/or causing major conformational changes of the receptor. This is the first report on the construction of a bispecific diabody with acquired novel antagonistic activity.

Permanent cardiovascular protection from hypertension by the AT(1) receptor antisense gene therapy in hypertensive rat offspring

Our previous studies have demonstrated that the introduction of angiotensin II type I receptor antisense (AT(1)R-AS) cDNA by a retrovirally mediated delivery system prevents the development of hypertension in the spontaneously hypertensive rat (SHR), an animal model for primary hypertension in humans. These results have led us to propose the hypothesis that an interruption of the renin-angiotensin system (RAS) activity at a genetic level would prevent hypertension on a permanent basis. F(1) and F(2) generations of offspring from a retroviral vector, LNSV- and LNSV-AT(1)R-AS-treated SHR, were generated, and various physiological parameters indicative of hypertension were studied and compared with those of their parents to investigate this hypothesis. Both F(1) and F(2) generations of LNSV-AT(1)R-AS-treated SHR expressed a persistently lower blood pressure, decreased cardiac hypertrophy and fibrosis, decreased medial thickness, and normalization of renal artery excitation-contraction coupling, Ca(2+) current, and [Ca(2+)](i) when compared with offspring derived from the LNSV-treated SHR. In fact, the magnitude of the prevention of these pathophysiological alterations was similar to that observed in the LNSV-AT(1)R-AS-treated SHR parent. The prevention of cardiovascular pathophysiology and expression of normotensive phenotypes are, at least in part, a result of integration and subsequent transmission of AT(1)R-AS from the SHR parents to offspring. These data demonstrate that a single intracardiac injection of LNSV-AT(1)R-AS causes a permanent cardiovascular protection against hypertension as a result of a genomic integration and germ line transmission of the AT(1)R-AS in the SHR offspring.