Increased mitochondrial-encoded gene transcription in immortal DF-1 cells

We have established, in continuous cell culture, a spontaneously immortalized chicken embryo fibroblast (CEF) cell line (DF-1) as well as several other immortal CEF cell lines. The immortal DF-1 cells divided more rapidly than primary and other immortal CEF cells. To identify the genes involved in rapidly dividing DF-1 cells, we have used differential display RT-PCR. Of the numerous genes analyzed, three mitochondrial-encoded genes (ATPase 8/6, 16S rRNA, and cytochrome b) were shown to express at higher levels in DF-1 cells compared to primary and other immortal CEF cells. The inhibition of mitochondrial translation by treatment with chloramphenicol markedly decreased ATP production and cell proliferation in DF-1 cells, while not affecting growth in either primary or other immortal CEF cells. This result suggests a correlation between rapid cell proliferation and the increased mitochondrial respiratory functions. We also determined that the increased transcription of mitochondrial-encoded genes in DF-1 cells is due to increased de novo transcript synthesis as shown by mitochondrial run-on assays, and not the result of either increased mitochondrial biogenesis or mitochondrial transcript half-lives. Together, the present studies suggest that the transcriptional activation of mitochondrial-encoded genes and the elevated respiratory function should be one of the characteristics of rapidly dividing immortal cells.

Co2(CO)8-mediated endo mode cyclization of epoxy-alcohol: synthesis of 2-ethynyl-3-hydroxy-2-methyltetrahydropyran and 2-ethynyl-3-hydroxy-3-methyltetrahydropyran derivatives

Successive treatment of 4,5-epoxy-5-methyl-7-trimethylsilyl-6-heptyne-1-ol with Co2(CO)8 at 0 degrees C and a catalytic amount of BF3 x OEt2 at -78 degrees C gave the tetrahydropyran derivatives with the cobalt-complexed moiety. Similarly 4,5-epoxy-4-methyl-7-trimethylsilyl-6-heptyne-1-ol underwent ring closure under the above conditions to provide the corresponding tetrahydropyran derivatives. The preferential endo mode cyclization over the exo one was observed in these experiments.

Molecular characterization of cDNA clones for ADP-glucose pyrophosphorylase from Citrus

Two cDNA clones encoding ADP-glucose pyrophosphorylases have been isolated from fruit and leaf cDNA libraries of Citrus (Citrus unshiu Mac. cv. Miyagawa) in which one was designated as agpS for the small subunit and the other as agpL for the large subunit. Both cDNAs have uninterrupted open reading frames deriving 57-58 kDa polypeptides. The deduced amino acid sequence of agpS has a unique feature. That is, it lacks a cysteine residue (Cys-12) which is usually conserved in all other dicot enzymes. This is the first report of agpS lacking Cys-12 among dicot small subunits. The expression pattern of both subunits showed a different profile in which leaves synthesized both agpS and agpL more vigorously than those of fruits. During leaf development, the transcripts of agpS and agpL showed a higher expression level at younger stages. During fruit development, the expression level of both subunits was observed to be highest in the mini-green stage, but it decreased in the small green stage and it increased again towards the maturing stage. These results suggest that both subunits may play an important role in the regulation of Citrus fruit and leaf development.

Total syntheses of tumor-related antigens N3: probing the feasibility limits of the glycal assembly method

The total syntheses of two octasaccharide antigens isolated from human milk, 1 and 2, and their corresponding allyl glycosides, 3 and 4, have been achieved by utilizing the glycal method. Convergent assembly of the core hexasaccharides and concurrent introduction of two alpha-L-fucosyl moieties at the late stage of the syntheses provided these complex carbohydrates in a concise manner. With synthetic material obtained, biological evaluations of these antigens as potential gastrointestinal cancer immunotherapeutic agents have been initiated.

Characteristics of bursal T lymphocytes induced by infectious bursal disease virus

Infectious bursal disease virus (IBDV) is an avian lymphotropic virus that causes immunosuppression. When specific-pathogen-free chickens were exposed to a pathogenic strain of IBDV (IM), the virus rapidly destroyed B cells in the bursa of Fabricius. Extensive viral replication was accompanied by an infiltration of T cells in the bursa. We studied the characteristics of intrabursal T lymphocytes in IBDV-infected chickens and examined whether T cells were involved in virus clearance. Flow cytometric analysis of single-cell suspensions of the bursal tissue revealed that T cells were first detectable at 4 days postinoculation (p.i.). At 7 days p.i., 65% of bursal cells were T cells and 7% were B cells. After virus infection, the numbers of bursal T cells expressing activation markers Ia and CD25 were significantly increased (P<0.03). In addition, IBDV-induced bursal T cells produced elevated levels of interleukin-6-like factor and nitric oxide-inducing factor in vitro. Spleen and bursal cells of IBDV-infected chickens had upregulated gamma interferon gene expression in comparison with virus-free chickens. In IBDV-infected chickens, bursal T cells proliferated in vitro upon stimulation with purified IBDV in a dose-dependent manner (P<0.02), whereas virus-specific T-cell expansion was not detected in the spleen. Cyclosporin A treatment, which reduced the number of circulating T cells and compromised T-cell mitogenesis, increased viral burden in the bursae of IBDV-infected chickens. The results suggest that intrabursal T cells and T-cell-mediated responses may be important in viral clearance and promoting recovery from infection.

Enhanced detection of left atrial spontaneous echo contrast by transthoracic harmonic imaging in mitral stenosis

BACKGROUND

Spontaneous echo contrast (SEC) of the left atrium is associated with increased risk of thromboembolism in patients with mitral stenosis (MS). The determination of the presence and severity of left atrial (LA) SEC is of prognostic importance in these patients. Harmonic imaging (HI), a novel echocardiographic technique that differs from conventional fundamental imaging (FI) in that it involves transmitting ultrasound at one frequency and receiving at twice the transmitted frequency, produces better endocardial border definition and myocardial opacification. However, there are no data about its value for the detection of LA SEC. The purpose of this study was to investigate the utility of transthoracic noncontrast tissue HI in the detection of LA SEC in patients with MS.

METHODS

Seventy-four consecutive patients with MS (49 women, mean age 51 years) underwent standard transthoracic echocardiography (TTE) in both HI and FI modes and transesophageal echocardiography (TEE) to determine the presence and severity of LA SEC. Left atrial SEC was graded by TEE as either mild (only seen at high gain) or severe (visible in the entire left atrium at normal gain control of the equipment). The control group comprised 30 patients randomly selected from patients who did not have LA SEC at the TEE examination.

RESULTS

Atrial fibrillation was found in 46 patients (62.2%). The mean mitral valve area and mean mitral gradient were 1.0+/-0.3 cm(2) and 8.2+/-4.1 mm Hg, respectively. Nine patients (12.2%) had episodes of systemic embolism; 8 had stroke, and 1 had peripheral embolism. Left atrial thrombus was found in 11 patients (14.9%) by TEE. Left atrial SEC was present in all but one patient by TEE (mild in 35 patients, severe in 38). Fundamental imaging with TTE, however, revealed LA SEC in only 5 (6.8%) of the 73 patients. In contrast, with HI, LA SEC could be detected in 63 (86.3%) patients. In the detection of severe LA SEC, the sensitivities of FI and HI were 13.2% (5/38) and 100% (38/38), respectively. Left atrial SEC was not observed in control subjects by either FI or HI.

CONCLUSIONS

Transthoracic HI significantly enhances the detection of LA SEC in patients with MS.

Affinity maturation of natural antibody using a chain shuffling technique and the expression of recombinant antibodies in Escherichia coli

The affinity of natural antibody (Ka = 8 x 10(6) M(-1)) recognizing preS1 of hepatitis B virus (HBV) was improved by replacing the heavy (H) chain gene with repertoires of VH genes, obtained from two nonimmunized donors. Two separate clones, 1C2 and 1E4, showed affinities of 2.3 x 10(7) and 5.2 x 10(7) M(-1), which were increased by factors of 2.8 and 6.5, respectively, compared to the parental clone. Recombinant scFvs (rscFvs) were expressed as fusion protein with minor coat protein, pIII, and secreted into medium after 3 h of induction with 1 mM IPTG. The expression level of functional rscFv capable of binding to preS1 reached a peak after 6-10 h (1C2) and 8-10 h (1E4) of IPTG induction, and afterwards decreased gradually. In order to achieve the overexpression of rscFv in E. coli, gene encoding scFv of 1C2 or 1E4 was inserted into pRSET vector. RscFvs were overexpressed as cytoplasmic inclusion bodies in E. coli BL 21 strain, which were denatured and carefully refolded using a continuous dialysis system. The purified recombinant fragments were pure when analyzed by SDS-PAGE and had the predicted size of 34 kDa. Clone 1E4 used the heavy chain gene belonging to family VII and subgroup III. Chain shuffling offers an alternative to random point mutation for affinity maturation of human antibody in vitro.

Germline mutations of the dpc4 gene in Korean juvenile polyposis patients

Juvenile polyposis is an uncommon condition characterized by the development of multiple (usually more than 5) juvenile polyps in the gastrointestinal tract, especially in the colon. This disease usually occurs during childhood, and is inherited in an autosomal dominant fashion. It has been suggested that the dpc4 (deleted in pancreatic carcinoma, locus 4) gene, which is located on chromosome 18q21.1, might cause juvenile polyposis. The dpc4 (smad4) gene is a candidate tumor-suppressor gene and may play a role in the TGF-beta-signaling pathway. To confirm the idea that alterations of the dpc4 gene may result in juvenile polyposis, we screened 5 Korean juvenile-polyposis patients by PCR-SSCP (single-strand conformation polymorphism) analysis and bi-directional sequencing. There were germline mutations of the dpc4 gene in 3 out of the 5 patients: 2 had a genetic alteration in exon 9 and the third had a mutation in exon 8. These germline mutations occurred in the C-terminus of the dpc4 gene, similar to most published mutations. One patient exhibited a non-sense mutation (codon 388), which changed a glutamine codon (CAG) to a stop codon (TAG). The second patient harbored a mis-sense mutation (codon 390), causing a non-conservative amino-acid change <glutamate (GAA) to lysine (AAA)>. The third patient had a mis-sense mutation in exon 8 (codon 361), which altered an arginine codon (CGC) into a histidine codon (CAC).

Nasal cycle in patients with septal deviation: evaluation by acoustic rhinometry

The nasal cycle in patients with septal deviation was studied by acoustic rhinometric techniques. This study included 24 patients with anteriorly located septal deviations (mean age = 23.5), and 26 normal controls (mean age = 24.7). Data of MCA (minimum cross-sectional area) and NV (nasal volume), collected in 20-minute intervals, were plotted for each subject during 8 hours. Twenty of 24 patients (83%) with septal deviation and 20 of 26 normal subjects (77%) showed at least one complete cycle. Duration of the nasal cycle, which ranged from 100 minutes to 400 minutes, had no statistical difference between the septal deviation group (mean duration of 216 minutes) and the normal control group (mean duration of 227 minutes). The degrees of variation of MCA and NV, defined as Degree of Variation of MCA (%) = 100 (MCAmax - MCAmin)/MCAmax, Degree of Variation of NV (%) = 100 (NVmax - NVmin)/NVmax, which represent the percent change of MCA and NV throughout the study, showed no difference between the wide side and the narrow side, or between the septal deviation group and the normal control group. These findings suggest that the nasal cycle is relatively independent of peripheral anatomic factors for its generation. However, the amplitude of changes of MCA was greater in the wide side, and the sum of both MCAs tended to fluctuate in accordance with the fluctuation of MCA of the wide side. Thus, the nasal cycle seemed to be affected by septal deviation.

Chiral separation of homocysteine by derivatization with 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole followed by capillary electrophoresis using gamma-cyclodextrin

Homocysteine was derivatized with 4-aminosulfonyl-7-fluoro-2,1,3-benzoxadiazole (ABD-F) to form an inclusion complex with cyclodextrin and to facilitate UV detection. ABD-homocysteine showed interaction with beta- and gamma-cyclodextrin in capillary electrophoresis at pH 2.25 as indicated by the decreased migration time. However, chiral separation of D,L-ABD-homocysteine was observed using gamma-CD only. Optimal separation was obtained at pH 2.25, 50 mM gamma-CD concentration, and 20 kV applied voltage. L-ABD-Homocysteine migrated faster than the D-isomer as demonstrated by a spiking experiment using dithiothreitol-reduced L-homocystine.

IBDV-induced bursal T lymphocytes inhibit mitogenic response of normal splenocytes

We examined the suppressive activity of bursal T cells induced by infectious bursal disease virus (IBDV) in inbred (15x7) and outbred commercial specific-pathogen-free (SPF) chickens. The suppressive activity was measured by the ability of bursal and splenic T cells from IBDV-infected chickens to inhibit mitogenic responses of normal splenocytes. The bursacytes but not the splenocytes of IBDV-infected chickens inhibited the mitogenic responses of normal splenocytes. The mitogenic inhibition by the bursacytes of IBDV-infected chickens was dose-dependent. The suppression was observed both in inbred and non-inbred chickens, and thus, was non MHC-restricted. Cell-sorting experiments revealed that both CD4(+) and CD8(+) cells from the bursa of IBDV-infected chickens, as well as cell-culture supernatants conditioned by these cells, mediated suppression. Suppressor T (Ts) cells may therefore be involved in the immunosuppression induced by IBDV.

Expression of the chloroplast-localized small heat shock protein by oxidative stress in rice

A rice (Oryza sativa L. cv. Nakdong) cDNA clone, Oshsp26, encoding the chloroplast-localized small heat shock protein (smHSP) was isolated. Southern blot analysis of genomic DNA and the result of screening of a cDNA library indicated that the Oshsp26 gene is encoded by a single gene in the rice genome. The Oshsp26 gene was expressed following heat stress: the transcript level was highest when rice leaves were treated at high temperatures for 2h at 42 degrees C, and the transcripts became detectable after 20min and reached a maximum level after 2h. It was also found that the Oshsp26 gene was expressed following oxidative stress even in the absence of heat stress. Treatment of rice plants with methyl viologen (MV) in the light and treatment with hydrogen peroxide (H(2)O(2)), either in the light or in the dark, both caused a significant accumulation of the transcripts and the protein. Since MV treatment in the light leads to the generation of H(2)O(2) inside the chloroplast, it is likely that H(2)O(2) by itself acts to induce the expression of the Oshsp26 gene. These results suggest that the chloroplast smHSP plays an important role in protecting the chloroplast against damage caused by oxidative stress as well as by heat stress.

Infectious bursal disease virus of chickens: pathogenesis and immunosuppression

Infectious bursal disease virus (IBDV) is an important immunosuppressive virus of chickens. The virus is ubiquitous and, under natural conditions, chickens acquire infection by the oral route. IgM+ cells serve as targets for the virus. The most extensive virus replication takes place in the bursa of Fabricius. The acute phase of the disease lasts for about 7-10 days. Within this phase, bursal follicles are depleted of B cells and the bursa becomes atrophic. Abundant viral antigen can be detected in the bursal follicles and other peripheral lymphoid organs such as the cecal tonsils and spleen. CD4(+) and CD8(+) T cells accumulate at and near the site of virus replication. The virus-induced bursal T cells are activated, exhibit upregulation of cytokine genes, proliferate in response to in vitro stimulation with IBDV and have suppressive properties. Chickens may die during the acute phase of the disease although IBDV induced mortality is highly variable and depends, among other factors, upon the virulence of the virus strain. Chickens that survive the acute disease clear the virus and recover from its pathologic effects. Bursal follicles are repopulated with IgM(+) B cells. Clinical and subclinical infection with IBDV may cause immunosuppression. Both humoral and cellular immune responses are compromised. Inhibition of the humoral immunity is attributed to the destruction of immunoglobulin-producing cells by the virus. Other mechanisms such as altered antigen-presenting and helper T cell functions may also be involved. Infection with IBDV causes a transient inhibition of the in vitro proliferative response of T cells to mitogens. This inhibition is mediated by macrophages which are activated in virus-exposed chickens and exhibit a marked enhancement of expression of a number of cytokine genes. We speculate that T cell cytokines such as interferon (IFN)-gamma may stimulate macrophages to produce nitric oxide (NO) and other cytokines with anti-proliferative activity. Additional studies are needed to identify the possible direct immunosuppressive effect of IBDV on T cells and their functions. Studies are also needed to examine effects of the virus on innate immunity. Earlier data indicate that the virus did not affect normal natural killer (NK) cell levels in chickens.

Expression of leptin receptor (Ob-R) in human atherosclerotic lesions: potential role in intimal neovascularization

Neovascularization of the adventitial vasa vasorum with extension into the intima of atherosclerotic lesions is frequently observed, but its pathophysiological significance is still subject to debate. Recently, leptin, the product of the Ob gene, was identified. Leptin, via activation of the endothelial receptor (Ob-R), generates a growth signal involving a tyrosine kinase-dependent intracellular pathway and promotes angiogenic processes. We hypothesized that a high concentration of leptin within vasa vasorum and plaque itself, may influence inflammatory and vascular neovascularization coupling with functional upregulation of the vascular endothelial growth factor (VEGF). Microscopic computerized tomography was utilized for the spatial distribution of vasa vasorum and intimal neovascularization from atherosclerotic human coronary arteries. Atherosclerotic coronary arteries showed a dense plexus of microvessels in the adventitia and plaque itself. Microscopic analysis from human atherosclerotic aortas revealed an increase in the intimal thickness with neovascularization. The immunoreactivity for Ob-R, VEGF and matrix metalloproteinase (MMP) increased in atherosclerotic plaque, predominantly in the endothelial lining of the intimal neovessel and macrophages/foam cells. Our observation of a prominent colocalization between Ob-R, VEGF and MMP supports this hypothesis and these factors participate in the neovascularization of atherosclerotic lesions. The present study is the first report on vascular tissue and it opens a promising perspective concerning future investigations of leptin-dependent modulation of atherogenesis and vascular neovascularization under pathophysiolgical conditions.

Coexpression of cyclooxygenase-2 and matrix metalloproteinases in human aortic atherosclerotic lesions

Inflammation appears to have a major role in the development of atherosclerosis. Cyclooxygenase-2 (COX-2) is involved in the inflammatory response via the generation of prostanoids that, in turn, are involved in the production of matrix metalloproteinases (MMPs). This study aimed to investigate atherosclerosis in human aortas for in situ tissue distribution of COX-2, MMPs including MMP-9 and membrane type 1 MMP (MT1-MMP), and tissue inhibitor of metalloproteinase-2 (TIMP-2). Immunohistochemical studies were performed on atherosclerotic lesions of aortas from patients with aortic aneurysms (n = 4) and dissections (n = 3) by using antibodies to COX-2, MMP-9, MT1-MMP, and TIMP-2. Control tissues were obtained from traumatically dissected aortas (n = 2). All specimens from diseased aortas had atherosclerotic lesions ranging from fatty streak to atheromatous plaques. In control, there was no expression of COX-2, MMP-9, and MT1-MMP in all aortic layers. Immunoreactivity for COX-2 was predominantly noted in macrophages and smooth muscle cells (SMCs) of the intima including atherosclerotic plaque itself and the medial layer of the plaque base, as well as in SMCs and endothelial lining of the vasa vasorum in the adventitia. Immunoreactivity for MMP-9 and MT1-MMP was found in the same distribution as that of COX-2. Additionally, the expression of TIMP-2 increased in relation to MMP-9 expression. This study demonstrates that COX-2 is coexpressed with MMP-9 and MT1-MMP, not only by macrophages and SMCs in atherosclerotic lesions, but also in endothelial lining of the vasa vasorum of human aortas. Thus, vascular inflammatory reactions may influence extracellular matrix remodeling by coactivation of MMPs in the development of atherosclerosis and, in turn, the progression of disease.

Usefulness of cilostazol versus ticlopidine in coronary artery stenting

A combination of ticlopidine and aspirin has been accepted as the standard antithrombotic regimen after coronary stenting. However, ticlopidine poses serious side effects such as neutropenia or thrombocytopenia. Cilostazol, a cyclic adenosine monophosphate phosphodiesterase inhibitor, is a novel antiplatelet agent with vasodilatory properties. We compared the efficacy and safety of cilostazol plus aspirin (C+A) with ticlopidine plus aspirin (T+A) in elective coronary stenting. Three hundred patients were randomly assigned to receive C+A or T+A 2 days before stenting. The primary end point was a composite of angiographic stent thrombosis, or major cardiac events (death, myocardial infarction, bypass surgery, repeat intervention) at 30 days. The secondary end points were bleeding vascular complications, neutropenia, thrombocytopenia, or side effects requiring discontinuation of the drugs at 30 days. The primary end point was reached in 1.4% in the C+A group and 2.0% in the T+A group (p = 1.0). The rate of bleeding vascular complications was 1.4% in the C+A group and 2.0% in the T+A group (p = 1.0). The rate of drug-related side effects was not statistically different between the 2 groups but slightly higher in the T+A group than in the C+A group (2.7% vs 0.7%, p = 0.37). However, neutropenia was seen in 2 patients only in the T+A group. As a poststenting antithrombotic, C+A is as effective as T+A in preventing major cardiac events including stent thrombosis, and safer in that it does not cause neutropenia despite the fact that there is no statistical difference in the incidence of adverse effects and complications.

Percutaneous transmyocardial revascularization induces angiogenesis: a histologic and 3-dimensional micro computed tomography study

The purpose of this study was to visualize the spatial patterns and connection of channels created after percutaneous transmyocardial revascularization (PTMR) in normal porcine hearts, and to estimate the relative contributions of transmyocardial and coronary perfusion. Six pigs underwent PTMR creating channels using radiofrequency ablative energy. Three-dimensional computed tomography imaging of channels 1 hr after PTMR showed the direct connection of PTMR channels to the myocardial capillary network and to epicardial coronary vessels. In the heart, examined 28 day after PTMR, there was a fine, extensive, network of microvessels originating from the site of the original PTMR channel, also connecting the left ventricular cavity to myocardial capillaries. Histopathologic examination of the 1-hr specimens showed numerous regions of myocardial hemorrhage and associated inflammatory cell infiltration. In the 28-day specimens, newly developed new vascular network suggested neovascularization within the core of these channel remnants. The immunoreactivity for basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) were intense within myocardium and neovascular structure surrounding PTMR channel remnants. The vascular connections occur by direct communication with existing myocardial vasculature acutely, and angiogenesis in these channel remnant chronically.

Congenital annular multiple fibrofolliculomas occurring with deformity of the ear and ventricular septal defect

We describe a 5-year-old girl who had multiple fibrofolliculomas with an unusual annular configuration, present since birth, localized to the mid-back. She had no family history of similar skin lesions. Examination showed a depigmented patch on her left buttock and other congenital anomalies, i.e. deformity of the auricle of the ear and ventricular septal defect. There has been no previous report of congenital multiple fibrofolliculomas occurring with congenital malformations such as deformity of the auricle of the ear and ventricular septal defect. The congenital occurrence and unusual configuration of the lesions in our patient may suggest a naevoid origin for these tumours.

Apolipoprotein E polymorphism in non-diabetic patients with acute coronary syndrome

Since a decade ago, apolipoprotein (apo) E polymorphism has been focussed as a risk factor for cardiovascular disease. ApoE plays a central role as a receptor ligand for the uptake of lipoproteins from the circulation. There was an agreement on apoE polymorphism being one of the major risk factors for coronary artery disease (CAD) by its effects on lipid profiles. However, the effects of apoE have not been noted in all populations and conflicting results in the risk of CAD have been noted. Recently, in situ expression of apoE on the atherosclerotic plaque has been studied. We, therefore, investigated the effects of apoE genotype on patients with acute coronary syndrome, including unstable angina and acute myocardial infarction, in non-diabetic patients. While we could not find significant risk effects of apoE on coronary artery disease and lipid profiles on simple comparison with the normal control group, we could find significantly decreased frequencies of apo epsilon 3 allele in patients with acute coronary syndrome compared with stable angina patients (77.8% vs 88.8%). We suggest that the apoE genotype could be associated with acute coronary events in CAD and further study with in situ biochemical methods will be needed on the effects of apoE polymorphism on plaque stability.

Recovery of antibody-producing ability and lymphocyte repopulation of bursal follicles in chickens exposed to infectious bursal disease virus

We studied the long-term effect of infectious bursal disease virus (IBDV) in chickens. Specifically, the restoration of virus-induced bursal lesions and the duration of humoral immunodeficiency were examined. One-week-old specific-pathogen-free chickens were intraocularly inoculated with an intermediate vaccine strain (IBDV-Vac) or a virulent strain (IM-IBDV). At intervals postinoculation (PI), chickens were examined for histopathologic lesions. At 1, 3, 5, 10, or 15 wk PI, the chickens were injected with a mixture of antigens, and primary antibody responses were examined at 10 days postimmunization. Initially, the virus caused extensive necrosis of bursal B lymphocytes. This lesion was accompanied by an infiltration of T lymphocytes. With time, the necrotic lesion in the bursa was resolved. The follicles became partly repopulated with B lymphocytes. The repopulation occurred faster in the chickens exposed to IBDV-Vac than in the chickens exposed to IM-IBDV. By 7 wk PI, 40% and 80% of bursal follicles in IM-IBDV- and IBDV-Vac-inoculated chickens, respectively, were repopulated with immunoglobulin M+ B lymphocytes. Both IBDV-Vac and IM-caused suppression of the primary antibody response to antigens. However, the antibody responses of the chickens exposed to either of the two IBDV strains used were compromised only during the first 6 wk of virus exposure. Subsequently, the antibody response returned to near normal levels.

Molecular cloning of multiple splicing variants of JIP-1 preferentially expressed in brain

Stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) is activated by a variety of cellular or environmental stresses. Proper regulation of the SAPK/JNK pathway may be critical for cell survival or death under various conditions. In this study, we report the molecular cloning of novel isoforms of JIP-1, which harbor a putative phosphotyrosine interaction domain and a helix-loop-helix domain, as well as an SH3 homologous region in the C terminus. Northern analysis indicates that transcription variant jip-1 is expressed in brain and kidney and transcription variants jip-2 and jip-3 are specifically expressed in brain. In situ hybridization data showed that the hybridized jip messages were heavily concentrated in adult brain, and were particularly enriched in the cerebral cortex and hippocampus, the brain regions vulnerable to pathological states such as hypoxia-ischemia, epilepsy, and Alzheimer's disease. All the deduced protein products of the jip transcription variants appear to have a similar property in that they inhibit the SAPK/JNK stimulation when overexpressed. Inhibition of SAPK activation by overexpression of the novel isoform JIP-2a resulted in suppression of etoposide-induced cell death in a neuroglioma cell line, N18TG. These findings suggest that JIP may play an important role in regulation of the SAPK pathway that is involved in stress-induced cellular responses.

Generation of human Fab monoclonal antibodies against preS1 of hepatitis B virus using repertoire cloning

Human monoclonal antibodies (MAbs) have considerable potential in the prevention and treatment of many viral diseases. A combinatorial antibody library of heavy (Fd)- and light-chain genes derived from peripheral blood lymphocytes of a volunteer with high antibody titer to preS1 of HBV was constructed and expressed on the surface of filamentous phages. The library contained 7 x 10(9) independent clones. A phage antibody population from the third panning against preS1 was converted to one expressing soluble Fabs by removal of the g3 sequences from the pComb3 phagemid vector and subsequent transformation into E. coli TG1 cells. Screening of the library led to the identification of two clones, 3DW and 8GW, showing high reactivity toward preS1. The authenticity of the Fabs was confirmed by immunoblot analysis which yielded approximately 60 and approximately 30 kDa bands under nonreducing and reducing conditions, respectively. The soluble Fabs of 3DW and 8GW exhibited relative affinities of 6 x 10(5) and 8 x 10(6) M(-1), respectively. The sequencing results demonstrate that all Fd sequences belong to subgroup II and all light chain sequences belong to subgroup I. There are differences in CDR length and composition, especially in the FW3 and CDR3 regions of the heavy- and light-chain genes. These human Fab MAbs specific to preS1, generated from a combinatorial library, represent prototypes of passive immunotherapy candidates for viral hepatitis B.

Experimental hypercholesterolemia induces ultrastructural changes in the elastic laminae of rabbit aortic valve

Atherosclerosis is the most severe problem in the high-pressure systemic circulation and similar changes also occur in the high-pressure loading valve. This study was designed to test the hypothesis that early atherosclerosis, induced by a high cholesterol diet in rabbits, is characterized by significant ultrastructural change in the elastic laminae of the aortic valve. However, it is not known whether this process is also taking place in the cardiac valve at the early stage of atherosclerosis. Animals were fed either a high cholesterol diet (n = 5) or a control diet (n = 5) for 10-12 weeks. Histologic analysis demonstrated that subendothelial thickening and foam-cell infiltration were evident in the arterialis of aortic valves. Confocal microscopy revealed an altered pattern characterized by fragmentation and disorganization of the arterialis elastic laminae of hypercholesterolemic valves. Computerized digital analysis of the images obtained by confocal scanning microscopy demonstrated that compared to normal valves, the arterialis elastic laminae of hypercholesterolemic valves decreased in percentage of their elastin content (29.03 +/- 1.10% vs. 42.94 +/- 1.35%, p = 0.023). Immunohistochemical staining for matrix metalloproteinase-3 (MMP-3) revealed MMP-3 immunoreactivity was increased in hypercholesterolemic valves, predominantly in the arterialis. This study demonstrated that early atherosclerosis, induced by a high cholesterol diet in rabbits, is characterized by significant ultrastructural change in the elastic laminae of the aortic valve. The arterialis endothelium of the aortic valve may be a more atherosclerosis-prone area compared with the ventricularis. The presence of ultrastructural defect in the elastic laminae may play a role in chronic degenerative change and a resultant valvular dysfunction.