Egg-adapted replication-restricted virus protects mice against lethal influenza

Infection of mice with the egg-adapted (EA) strain of influenza virus was studied as a murine model of human live attenuated virus vaccine. The growth and spread of the EA virus in the mouse lungs were restricted, and only small inflammatory changes were detected in the respiratory tracts. Deletion and substitutions of amino acids were found in the hemagglutinin molecule of the EA virus, which were attributable to the reduced envelope fusion activity in virus multiplication cycles. Intranasal inoculation of mice with the EA virus induced specific IgG and IgA antibody production together with a specific cytotoxic T lymphocyte response. Immunized mice showed a distinct resistance to subsequent lethal challenge with the virulent influenza virus. These results indicate that the mutant virus loaded with a growth restriction in the respiratory tract is an appropriate candidate for a live attenuated vaccine.

Reconstructing the duplication history of a tandem repeat

One of the less well understood mutational transformations that act upon DNA is tandem duplication. In this process, a stretch of DNA is duplicated to produce two or more adjacent copies, resulting in a tandem repeat. Over time, the copies undergo additional mutations so that typically, multiple approximate tandem copies are present. An interesting feature of tandem repeats is that the duplicated copies are preserved together, making it possible to do "phylogenetic analysis" on a single sequence. This involves using the pattern of mutations among the copies to determine a minimal or a most likely history for the repeat. A history tries to describe the interwoven pattern of substitutions, indels, and duplication events in such a way as to minimize the number of identical mutations that arise independently. Because the copies are adjacent and ordered, the history problem can not be solved by standard phylogeny algorithms. In this paper, we introduce several versions of the tandem repeat history problem, develop algorithmic solutions and evaluate their performance. We also develop ways to visualize important features of a history with the goal of discovering properties of the duplication mechanism.

[Morphological and microscopic identification of herba artemisiae scopariae and its adulterants]

Pharmacognostical studies of Herba Artemisiae Scopariae and its adulterants were compared on morphological and microscopic characteristics. The detailed characteristics of powder microscopic identification were described.

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part V. Use of the flap in the inguinal region and latissimus dorsi musculocutaneous flap

The area of distribution of the superficial circumflex iliac, superficial epigastric and superficial external pudental arteries is large and flaps based on them can meet the requirement of different recipient sites. We have transplanted free flaps based on the superficial epigastric artery for repairing plantar soft tissue defects in six leprosy patients. During the follow-up examination 58 to 118 months later there has been no recurrence of ulceration in any of these cases. The latissimus dorsi muscle, is mainly nourished by the thoracadorsal artery and the latissimus dorsi musculocutaneous flap is a large sized, composite structure with abundant blood provision and strong anti-infectious property. The latissimus dorsi flap can be used as an artery-pedicled island flap or as a free flap besides its use as a muscle graft, because of its constant vascular position, wide outer-diameter of the vessels and long pedicle. It can therefore be utilized for repairing soft tissue defect or replacement of paralyzed muscle. We have used the latissimus dorsi musculocutaneous free flap for repairing large skin and soft tissue defects resulting from plantar ulceration in three leprosy patients. During the follow-up period, one patient who had complete drop-foot and had refused corrective surgery had recurrence of the ulcer in the 12th post-operative month. No ulcers had recurred in the other two cases during the follow-up at 48 and 114 months.

Alternation of Na(+)-Ca2+ exchange in rat cardiac sarcolemmal membranes during different phases of sepsis

OBJECTIVE

To study the alteration of Na(+)-Ca2+ exchange in rat cardiac sarcolemmal membrane during phases of septic shock.

METHODS

Sepsis was induced by cecal ligation and puncture (CLP). Na(+)-Ca2+ exchange was assayed by radioactive analysis.

RESULTS

Na(+)-dependent 45Ca2+ uptake was decreased by 62%-69% in late phase of sepsis, whereas it was not affected in early phase of sepsis. Na(+)-Ca2+ exchange stimulated by 5' guanylyl imidodiphosphate [Gpp (NH) p] was decreased by 65.7% in late phase of sepsis but unaltered in early phase of sepsis. Two agonists (angiotensin II and phenylephrine) coupled to Gq and a protein kinase C activator, phorbol 12-myristate 13-acetate (PMA) all inhibited Na(+)-Ca2+ exchange in late phase of sepsis. Na(+)-Ca2+ exchange activities induced by phosphorylation of Na(+)-Ca2+ exchange were decreased in late phase of sepsis, whereas inhibition of Na(+)-Ca2+ exchange by dephosphorylation was increased both in early and late phases of sepsis.

CONCLUSION

The alteration of Na(+)-Ca2+ exchange during different phases of sepsis might be related to the activities of Gq, protein kinase C, and phosphorylation/dephosphorylation.

Partial purification and characterization of the active entity responsible for inducing interleukin-6 production by human gingival fibroblasts from Mycoplasma salivarium cells

The active entity responsible for inducing interleukin-6 production by human gingival fibroblasts was partially purified by ion-exchange chromatography from the water-soluble fraction of Mycoplasma salivarium cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the final preparation revealed one densely stained band with a molecular weight of 20.6 kilodaltons and two faint bands with molecular weights of 40.5 and 82.5 kilodaltons. The specific activity of the final preparation was 34-fold higher than that of the starting water-soluble fraction. The interleukin-6-inducing activity was destroyed by proteinase K and reduced 70% by lipoprotein lipase and heat treatment, but was not affected by deoxyribonuclease I or endoglucosidase D. The final preparation induced small amounts of tumor necrosis factor-alpha and interleukin-lbeta in a myelomonocytic cell line, THP-1 cells, but did not induce interleukin-6. The ability of Escherichia coli lipopolysaccharide to stimulate human gingival fibroblasts to release interleukin-6 was dependent upon the presence of serum in the assay medium, but that of the final preparation from M. salivarium was not. Thus, we partially purified the protein(s) from M. salivarium which were capable of stimulating human gingival fibroblasts to release interleukin-6 by a mechanism different from that of E. coli lipopolysaccharide.

[Expression and its clinical significance of tissue factor pathway inhibitor and antithrombin-III in patients with hepatic inflammatory diseases]

OBJECTIVE

To investigate the change and clinical significance of tissue factor pathway inhibitor (TFPI) and antithrombin-III (AT-III) in the plasma of patients with hepatic inflammatory disease (HID).

METHODS

The plasma levels and activation of TFPI and AT-III in patients with HID (Group I, n = 82) were compared to that in healthy people (Group II as control, n = 30).

RESULTS

The plasma level of TFPI:Ag in Group I was higher (P < 0.05) and its activation was also increased dramatically (P < 0.01), the level of AT-III: A was lower in patients with chronic hepatitis B (P < 0.05) and no difference was found in other indices between the two groups.

CONCLUSIONS

The elevation of TFPI:Ag and TFPI:A in hepatic inflammatory diseases is an indication of inflammation, and hepatic tissue injury in broad, the lower level of AT-III liver secretions.

Mechanisms of transcriptional activation of bcl-2 gene expression by 17beta-estradiol in breast cancer cells

bcl-2 gene expression is induced by 17beta-estradiol (E2) in T47D and MCF-7 human breast cancer cells, and the mechanism of E2 responsiveness was further investigated by analysis of the bcl-2 gene promoter. The -1602 to -1534 distal region (bcl-2j) of the promoter was E2-responsive; however, in gel mobility shift assays, the estrogen receptor alpha (ER(alpha)) did not bind [(32)P]bcl-2j, whereas Sp1 protein formed a retarded band complex. Further analysis demonstrated that the upstream region (-1603 to -1579) of the bcl-2 gene promoter contained two GC/GA-rich sites at -1601 (5'-GGGCTGG-3') and -1588 (3'-GGAGGG-5') that bound Sp1 protein. Subsequent studies confirmed that transactivation by E2 was dependent on ER(alpha)/Sp1 interactions with both GC-rich sites, and this was confirmed by in vitro footprinting. In contrast, a 21-base pair E2-responsive downstream region (-1578 to -1534) did not bind Sp1 or ER(alpha) protein; however, analysis of a complex binding pattern with nuclear extracts showed that ATF-1 and CREB-1 bound to this motif. These data coupled with results of transient transfection studies demonstrated that transcriptional activation by E2 of the -1578 to -1534 region of the bcl-2 gene promoter was dependent on induction of cAMP and subsequent activation through a cAMP response element. Thus, hormone regulation of bcl-2 gene expression in breast cancer cells involves multiple enhancer elements and E2-mediated transactivation does not require direct binding of the estrogen receptor with promoter DNA.

Cross-reactivity of myelin basic protein-specific T cells with multiple microbial peptides: experimental autoimmune encephalomyelitis induction in TCR transgenic mice

Activation of autoreactive T cells is a crucial event in the pathogenesis of autoimmune diseases. Cross-reactivity between microbial and self Ags (molecular mimicry) is one hypothesis that could explain the activation of autoreactive T cells. We have systematically examined this hypothesis in experimental autoimmune encephalomyelitis using mice bearing exclusively myelin basic protein (MBP)-specific T cells (designated T+ alpha-). A peptide substitution analysis was performed in which each residue of the MBPAc1-11 peptide was exchanged by all 20 naturally occurring amino acids. This allowed the definition of the motif (supertope) that is recognized by the MBPAc1-11-specific T cells. The supertope was used to screen protein databases (SwissProt and TREMBL). By the search, 832 peptides of microbial origin were identified and synthesized. Of these, 61 peptides induced proliferation of the MBPAc1-11-specific transgenic T cells in vitro. Thus, the definition of a supertope by global amino acid substitution can identify multiple microbial mimic peptides that activate an encephalitogenic TCR. Peptides with only two native MBP-residues were sufficient to activate MBPAc1-11-specific T cells in vitro, and experimental autoimmune encephalomyelitis could be induced by immunizing mice with a mimic peptide with only four native MBP residues.

Spot synthesis: observations and optimizations

Positionally addressable syntheses of peptides on continuous cellulose membranes (spot synthesis) have often been reported in detail, but important questions dealing with synthesis quality, reproducibility and subsequent binding assays have largely been under-emphasized. In this report we have investigated some of these problems. The most important results were: (i) the signal intensity of ligate binding to cellulose-bound peptides and the affinity of the corresponding soluble peptides show good correlation, illustrated by three different ligate binding assays; (ii) reducing peptide density on the cellulose avoids the 'ring spot' effect, i.e. where less binding is observed in the spot-center compared to the rim. We recommend a peptide density of 10 nmol/cm2 as a reasonable starting point for further optimization; (iii) statistical analysis of binding assay reproducibility with more than 15000 peptides resulted in a mean standard signal deviation of 0.18; and (iv) optimization of side-chain deprotection revealed that a 30-min pretreatment of the cellulose with 90% trifluoroacetic acid followed by the standard deprotection protocol resulted in higher purity of the synthesized products.

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part III. Use of plantar skin or musculocutaneous flaps and anterior leg flap

Anatomical studies suggest that five types of plantar flaps namely, the lateral and medial plantar flaps, the Abductor hallucis-, the Flexor digitorum brevis-, and the Abductor digiti minimi-myocutaneous flaps, can be incised from the central section of the sole. The advantages of a plantar flap are recognizable neurovascular bundles of the sole, wide calibre of constantly located blood vessels, identical histological structure of the donor and the recipient sites, hidden donor site and absence of functional deficit. We have used the plantar flaps in seven cases. There has been no recurrence of ulceration in any of them during the follow-up period of 12 to 108 months. An anterior leg flap based on the cutaneous branches of the anterior tibial artery, with firmly anchored vessels, a long pedicle with wide vessels may be used not only as a free flap graft for reconstruction of moderate degree distant defects but also as a retrograde island flap graft for the reconstruction of adjacent tissue defect. We have used the retrograde island flap graft based on the anterior tibial artery in five cases of plantar ulceration with satisfactory results. There was no recurrence of ulceration during the follow-up period of 48 to 72 months.

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part IV. Use of medial leg flap and medial knee flap

The medial leg flap, based on the cutaneous branches of the posterior tibial artery is raised from the middle and lower regions of the medial aspect of the leg. It has a long pedicle, and it can be used as a free flap to reconstruct the distant soft tissue defects and also as an island flap. We have used this retrograde island flap for surfacing ulcerated areas in six leprosy patients. The flap survived in all cases. At 24 to 60 months follow-up examination, ulceration had not recurred in any of them. The medial knee flap consisting of the skin and subcutaneous tissue of the lower part of the medial side of the thigh and the upper part of the leg, is suitable for covering soft tissue cushion defects of the extremities because of the constant vessels, long pedicle, wide diameter, well-recognizable sensory nerves and less subcutaneous fat. We have used the medial knee flap for the resurfacing sizeable raw areas due to ulceration in three leprosy patients. The flap survived in all cases and there was no recurrence of ulceration during the 70-148 months follow-up period.

Detection of Mycoplasma fermentans in saliva sampled from infants, preschool and school children, adolescents and adults by a polymerase chain reaction-based assay

Attempts were made to detect Mycoplasma fermentans in saliva sampled from 201 subjects (108 males and 93 females) aged from 4 months to 59 years by a polymerase chain reaction-based assay. M. fermentans was detected in saliva from 110 (54.7%) of 201 subjects, and 10 (28.6%) of 35 subjects aged from 4 months to 3 years. Of ten positive subjects, three were aged from 16 to 23 months and five were from 26 to 31 months. The incidence tended to increase with age up to the teens. The incidence was significantly greater in teenagers than in subjects aged from 7 to 12 years, but there was no significant difference in the incidence between the group of teenagers and each of the groups of subjects older than the teenagers. Thus, it was suggested that M. fermentans colonized the mouth at the age of about 16 months up to the age of 19 years.

Transcriptional activation of E2F1 gene expression by 17beta-estradiol in MCF-7 cells is regulated by NF-Y-Sp1/estrogen receptor interactions

17beta-Estradiol (E2) stimulated proliferation and DNA synthesis in MCF-7 human breast cancer cells, and this was accompanied by induction of E2F1 mRNA and protein levels. Analysis of the E2F1 gene promoter showed that the -146 to -54 region was required for E2-responsiveness in transient transfection assays, and subsequent deletion/mutation analysis showed that a single upstream GC-rich and two downstream CCAAT-binding sites were required for transactivation by E2. Gel mobility shift assays with multiple oligonucleotides and protein antibodies (for supershifts) showed that the -146 to -54 region of the E2F1 gene promoter bound Sp1 and NF-Y proteins in MCF-7 cells. The estrogen receptor (ER) protein enhanced Sp1 interactions with upstream GC-rich sites, and interactions of ER, Sp1, and ER/Sp1 with downstream DNA bound-NF-Y was investigated by kinetic analysis for protein-DNA binding (on- and off-rates), coimmunoprecipitation, and pulldown assays using wild-type and truncated glutathione S-transferase (GST)-Sp1 chimeric proteins. The results showed that Sp1 protein enhanced the Bmax of NF-Y-DNA binding by more than 5-fold (on-rate); in addition, the Sp1-enhanced NF-Y-DNA complex was further stabilized by coincubation with ER and the rate of dissociation (t1/2) was decreased by approximately 50%. Sp1 antibodies immunoprecipitated [35S]NF-YA after coincubation with unlabeled Sp1 protein. Thus, transcriptional activation of E2F1 gene expression in MCF-7 cells by E2 is regulated by multiprotein ER/Sp1-NF-Y interactions at GC-rich and two CCAAT elements in the proximal region of the E2F1 gene promoter. This represents a unique trans-acting protein complex in which ligand-dependent transactivation by the ER is independent of direct ER interactions with promoter elements.

[Hypoxia-induced increase in nerve activity of rabbit carotid body mediated by noradrenaline]

The responses of 39 hypoxia-sensitive units of chemoreceptive afferent in sinus nerve to noradrenaline (NA) and its antagonist were recorded in carotid body-sinus nerve preparations from 30 rabbits. The results are as follows. (1) Discharges of the units increased from 0.13 +/- 0.06 to 0.25 +/- 0.12 imp/s (P < 0.001, n = 19) upon lowering PO2 of modified Tyrode solution. (2) Adding NA (10(-6) mol/L) to the perfusate led to an increase in the unit discharge from 0.14 +/- 0.08 to 0.23 +/- 0.13 imp/s (P < 0.01, n = 19). (3) Prazosin (10(-6) mol/L) did not alter the basal frequency of chemosensory unit discharges under normoxic conditions (P > 0.05, n = 4). (4) Yohimbine (10(-6) mol/L) did not alter the basal frequency of chemosensory unit discharges under normoxic conditions (P > 0.05, n = 6). (5) Chemosensory responses to hypoxia were not altered after pretreatment with prazosin. (6) Chemosensory responses to hypoxia were inhibited by pretreatment with yohimbine. The present results suggest that (1) NA is not mainly concerned with spontaneous discharges of chemoreceptor sensitive to hypoxia, but does elicit an increase in spontaneous discharges, and (2) the increase of chemosensory unit discharges produced by hypoxia can be inhibited by yohimbine. It is likely that the excitatory action of hypoxia on chemoreceptive process is mediated by NA.

Characterization of neutralizing anti-pre-S1 and anti-pre-S2 (HBV) monoclonal antibodies and their fragments

Single-chain Fv fragments (scFv) were generated from two murine monoclonal antibodies directed to the neutralizing epitopes of the pre-S1 and pre-S2 region of hepatitis B virus, respectively, using different assembly cloning strategies. The scFv fragments were solubly expressed in E. coli. Dissociation constants were in the nanomolar range for all forms (whole IgG antibodies, Fab fragment and scFv fragments). The epitopes of both antibodies were mapped using solid phase peptide synthesis on continuous cellulose membranes and turned out to be linear determinants. The minimal epitope for the anti-pre-S2 antibody 1F6 was identified to be DPRVRGLYF (amino acid 133-141 of the pre-S region). For the anti-pre-S1 antibody MA 18/7 the minimal epitope proved to be the hexamer LDPAFR (amino acid 30-35 of the pre-S region). Complete substitutional analyses as well as truncation experiments revealed key residues for these antibody-antigen interactions. On the basis of those results we used computer-assisted modeling techniques to suggest models for both antibody-peptide interactions providing insight into the structural basis of these molecular recognitions.

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part I--General considerations and summary of results

Recurrent plantar ulceration is a common and serious complication occurring consequent to impairment of the tibial nerve in leprosy patients. In spite of many therapies and long therapeutic course, it is extremely difficult to abolish this complication in many cases because of extensive skin and soft tissue cushion loss due to repeated infection. Since the early 70's we have been using microscopic surgical techniques to reconstruct the ulcerated area using eight types of the flaps. In this series of papers we review our experience (76 patients). Post-operatively, the flaps survived in all cases, the long-term results have proved satisfactory, and recurrent ulceration occurred in only three patients.

Systemic uptake and clearance of chloroform by hairless rats following dermal exposure: II. Absorption of the neat solvent

Blood concentrations of chloroform were monitored after exposing small areas (approximately 5.5 cm2) of the backs of hairless rats to liberal excesses of the solvent for either 1, 3, or 8 min. The amounts absorbed were quantified by comparing areas-under-the-curves (AUCs) of blood concentration versus time plots to the AUC obtained on infusing an aqueous chloroform solution of known concentration for 30 min (positive control). Chloroform penetrated the dermal barrier rapidly, the skin's horny layer and the deeper skin tissues acting as reservoirs for chloroform only for short durations. Evaporative and physiological clearance from these reservoirs was rapid once the chloroform was removed from the surface. Pressure of the template used to confine the exposure affected uptake. For blood levels, the time to reach the maximum blood concentration increased with increased exposure duration. Amounts absorbed also depended on exposure duration. Blood level profiles indicated systemic uptake of chloroform following a 3-min exposure was about 1.3-fold higher than for a 1-min exposure (not significant), while the 8-min exposure produced an AUC roughly 3.8-fold higher than found at 3 min (p = 0.026). Chloroform is rapidly cleared from rat blood (terminal elimination rate constant = 0.009/min). Calculations indicated that its absorption from these area-limited exposures far exceeds that which would be absorbed had the chloroform been presented to the skin as a saturated aqueous solution.

Techniques for covering soft tissue defects resulting from plantar ulcers in leprosy: Part II--First toe web and dorsal foot flaps

The first toe web flap consists of the skin and subcutaneous tissues of the contiguous sides between the great and second toes. It is based on the first dorsal metatarsal artery or the common plantar digital artery. This flap was used as artery pedicled island graft to reconstruct losses of skin and soft tissue cushion in the ball of the foot in the first and second metatarsal head region in 16 cases. Follow-up examination revealed that ulceration had recurred in one case due to dehiscence of the flap margin 12 months post-operatively. The other 15 patients have done well without recurrence at 48 to 124 months follow-up examination. The dorsal flap of the foot based on the dorsalis pedis artery, the corresponding veins and the deep peroneal nerve was designed in 1974 to resurface skin and soft tissue defects in the sole of the foot. This flap was used in 30 cases of leprosy with excellent results. During follow-up 36 to 120 months after surgery the plantar ulcer had recurred in only one case. All the others have done well. The long-term curative effect has thus proved satisfactory.

Transcriptional activation of mRNA of intercellular adhesion molecule 1 and induction of its cell surface expression in normal human gingival fibroblasts by Mycoplasma salivarium and Mycoplasma fermentans

Lipoproteins in the cell membranes of both Mycoplasma salivarium and Mycoplasma fermentans were demonstrated to trigger the transcription of intercellular adhesion molecule-1 mRNA in normal fibroblasts isolated from human gingival tissue and to induce its cell surface expression by a mechanism distinct from that of Escherichia coli lipopolysaccharide. The lipid moiety of the lipoproteins was suggested to play a key role in the expression of the activity.

High-power chirped-pulse all-fiber amplification system based on large-mode-area fiber gratings

We describe the fabrication of chirped gratings in a specially developed photosensitive large-mode-area fiber and report the use of these components in a picosecond all-fiber chirped-pulse-amplification circuit. We demonstrate the generation of microjoule energy pulses with peak powers in excess of 500 kW, which we believe to be a record peak power from an all-fiber system.

Differential expression of peroxiredoxin subtypes in human brain cell types

The peroxiredoxin (Prx) protein is expressed widely in animal tissues and serves an antioxidant function associated with removal of cellular peroxides. We have cloned two Prx genes and observed differential expression of Prx-I and Prx-II (formerly NKEF-A and NKEF-B) in purified rat brain cell cultures (Sarafian et al. [1998] Mol. Chem. Neuropathol. 34:39-51). We have examined regional and cell-type-specific expression of Prx-I and Prx-II in paraffin sections of human brain using immunohistochemical methods. These studies revealed a clear segregation of expression of these two gene products in different brain cell types. In the cerebral cortex, cerebellum, basal ganglia, substantia nigra, and spinal cord, Prx-I was expressed primarily in astrocytes, while Prx-II was expressed exclusively in neurons. Prx-I was also prominently expressed in ependymal cells and subependymal matrix of substantia nigra and basal ganglia. Prx-II was not expressed at uniform density in all neurons. In general, small neurons such as cerebellar granule neurons displayed little or no staining, while large neurons, such as hippocampal pyramidal and Purkinje neurons were heavily stained. The absence of expression of Prx-I in neurons and the selective expression of Prx-II in large neurons suggest that these antioxidant enzymes serve distinct functional roles that may reflect the different functions and biochemical activities of these cell types. Restricted expression of these genes may also contribute to the selective vulnerability of these cells to a wide variety of neuropathologic conditions.

[Study on the effect of ligustrazine on adherent molecule expression of bone marrow cells in immune-mediated aplastic anemia mice]

OBJECTIVE

To explore the effect of ligustrazine on the expression of adherent molecule of bone marrow cells in immune-mediated aplastic anemia(AA) mice.

METHODS

Each immune-mediated AA mouse was intraperitoneally injected with 5 mg ligustrazine twice a day. On the 14th day, expressions of CD49d and CD49c in bone marrow mononuclear cells(MNC) were detected by flow cytometry, and VCAM-1 on stromal cells by immunohistochemistry SABC.

RESULTS

Expressions of CD49d, CD49e and VCAM-1 were significantly lower in AA group than in normal group(t = 11.96, 17.18 and 7.09 respectively, P < 0.001), and were much higher in ligustrazine treated group than in non-treated group(t = 9.05, 14.61 and 6.91 respctively, P < 0.001). Expressions of CD49d and VCAM-1 were in the normal range in ligustrazine group.

CONCLUSIONS

Ligustrazine can increase the expression of adherent molecule of bone marrow cells in immune-mediated AA mice, thus promote the growth of hematopoietic cells.

Neural precursor cells differentiating in the absence of Rb exhibit delayed terminal mitosis and deregulated E2F 1 and 3 activity

The severe neurological deficit in embryos carrying null mutations for the retinoblastoma (Rb) gene suggests that Rb plays a crucial role in neurogenesis. While developing neurons undergo apoptosis in vivo neural precursor cells cultured from Rb-deficient embryos appear to differentiate and survive. To determine whether Rb is an essential regulator of the intrinsic pathway modulating terminal mitosis we examined the terminal differentiation of primary cortical progenitor cells and bFGF-dependent neural stem cells derived from Rb-deficient mice. Although Rb -/- neural precursor cells are able to differentiate in vitro we show that these cells exhibit a significant delay in terminal mitosis relative to wild-type cells. Furthermore, Rb -/- cells surviving in vitro exhibit an upregulation of p107 that is found in complexes with E2F3. This suggests that p107 may partially compensate for the loss of Rb in neural precursor cells. Functional ablation of Rb family proteins by adenovirus-mediated delivery of an E1A N-terminal mutant results in apoptosis in Rb-deficient cells, consistent with the interpretation that other Rb family proteins may facilitate differentiation and survival. While p107 is upregulated and interacts with the putative Rb target E2F3 in neural precursor cells, our results indicate that it clearly cannot restore normal E2F regulation. Rb-deficient cells exhibit a significant enhancement of E2F 1 and 3 activity throughout differentiation concomitant with the aberrant expression of E2F-inducible genes. In these studies we show that Rb is essential for the regulation of E2F 1 and 3 activity as well as the onset of terminal mitosis in neural precursor cells.

[Evaluation of atrial natriuretic peptide in differentiating benign and malignant pleural effusion]

OBJECTIVE

To discuss the value of atrial natriuretic peptide (ANP) in differentiating benign and malignant pleural effusion.

METHODS

Direct radioimmunoassay was used to detect ANP of pleural effusion and serum in 30 tuberculous and 26 cancerous pleural effusion patients.

RESULTS

The ANP in tuberculous and cancerous pleural effusion were (75 +/- 9) ng/L, (157 +/- 45) ng/L respectively, and significant difference was found (P < 0.001). The ANP of tuberculous pleural effusion was apparently lower [(75 +/- 9) ng/L] than serum [(170 +/- 37) ng/L], and significant difference was also found (P < 0.001). The ratio of ANP of pleural effusion to that of serum were 0.47 +/- 0.17, 0.99 +/- 0.46 respectively in tuberculous and cancerous pleural effusion patients. The sensitivity of ANP was 81% and specificity 100% in diagnosing malignant pleural effusion.

CONCLUSIONS

Detecting ANP of pleural effusion is one of important methods for differentiating benign and malignant pleural effusion.

Prevention of neuronal cell death by neural adhesion molecules L1 and CHL1

The effects of L1-Fc and CHL1-Fc fusion proteins on neuronal survival were investigated. Cerebellar granule neurons of mouse and hippocampal neurons of rat embryo undergo apoptosis when cultured in serum-free medium. Treatment with chimeric proteins containing the extracellular domains of the neural adhesion molecules L1 or CHL1 fused to the Fc region of human immunoglobulin significantly enhanced the survival of neurons. Compared to the control, the percentage of surviving neurons increased about 60% and 45% with L1 and CHL1 fusion proteins, respectively. A fusion protein containing the extracellular domain of NCAM had no effect on survival. The L1 and CHL1 fusion proteins were effective both in soluble form or when offered as a substrate, with the maximal effect at about 1 microg/mL. To explore the intracellular events related to the neuronal survival effects of L1-Fc fusion protein, Bcl-2 and c-Jun expression were analyzed by Western blotting. The level of Bcl-2 in cerebellar granule neurons was increased by treatment with L1-Fc at both 1 and 5 days of culture. The level of c-Jun was not significantly affected at the early time point and was reduced by L1-Fc fusion protein after long-term culture. The results demonstrate that the neural adhesion molecule L1 and its relative CHL1 are potential neuronal survival factors for neurons of the central nervous system. Bcl-2 may serve as one of the intracellular mediators of the neuronal survival effects of L1.

[Effect of composite blood-activating decoction on expression of adherent molecule and cyclin in bone marrow hematopoietic cells in mice of immune-induced aplastic anemia]

OBJECTIVE

To study the effect of composite blood-activating decoction (CBAD) on expression of adherent molecule CD49 d and cyclin D2 in bone marrow hematopoietic cells in experimental immune-mediated aplastic anemia (AA) mice.

METHODS

After the model of AA was established, the animals were fed with 0.2 ml of 100% CBAD, twice a day for 12 days. Te CD49 d and cyclin D2 expression level of bone marrow hematopoietic cells in model mice were measured by flow cytometor analysis system at the 13th day of experiment.

RESULTS

CD49 d expression level in CBAD group was significantly higher than that in the AA group (P < 0.05), and was similar to that in the normal group (P > 0.05). The expression of cyclin D2 in CBAD group was significantly higher than that in the AA group (P < 0.01), but the cell count of G0 + G1 phase was significantly lower in the CBAD group, as compared with the AA group, P < 0.01.

CONCLUSION

CBAD can increase the expression of adherent molecule CD49 d and cyclin D2 in bone marrow hematopoietic cells, and promote the growth of hematopoietic cells.

Effect of ligustrazine on expression of adherent molecule CD49d and cyclin D2 in hematopoietic cells in acute radiation injured mice

After irradiation by 8.0 Gy gamma-ray, each mouse was stomach-fed by 4 mg ligustrazine injection twice a day. On the 7th day after irradiation, CD49d expression in ligustrazine-treated group was significantly higher than that in control group (P < 0.01), and showed no difference from that in normal group (P > 0.05). On the 14th day after irradiation. CD49d expression was increased in control group, but decreased significantly in ligustrazine-treated group (P < 0.01). The expression of Cyclin D2 in spleen mononuclear cells (MNC) in ligustrazine-treated group was significantly higher than that in control group, but the ratio of G0 + G1 phase cells was significantly lower in ligustrazine-treated group (P < 0.01). This finding indicated that ligustrazine could increase the expression of adherent molecule on bone marrow hematopoietic cells and Cyclin D2 in spleen MNC, thereby promoting the growth of hematopoietic cells.

[The observations of plasma of AC operation in the CT-6B Tokamak by Ha emissions]

The spatial distribution and temporal evolution of plasma of AC operation in the CT-6B Tokamak has been observed through Ha emissions by an optical multichannel diagnostic system for the first time. The results show the plasma density is not completely lost during current reversal, therefore, there were no need for second breakdown after the current reversal. The spatial and temporal evolution of plasma is dependent on the current wave forms.

Glutamate potentiates the toxicity of mutant Cu/Zn-superoxide dismutase in motor neurons by postsynaptic calcium-dependent mechanisms

Mutations in the Cu/Zn-superoxide dismutase (SOD-1) gene are responsible for a subset of familial cases of amyotrophic lateral sclerosis. Using a primary culture model, we have demonstrated that normally nontoxic glutamatergic input, particularly via calcium-permeable AMPA/kainate receptors, is a major factor in the vulnerability of motor neurons to the toxicity of SOD-1 mutants. Wild-type and mutant (G41R, G93A, or N139K) human SOD-1 were expressed in motor neurons of dissociated cultures of murine spinal cord by intranuclear microinjection of plasmid expression vector. Both a general antagonist of AMPA/kainate receptors (CNQX) and a specific antagonist of calcium-permeable AMPA receptors (joro spider toxin) reduced formation of SOD-1 proteinaceous aggregates and prevented death of motor neurons expressing SOD-1 mutants. Partial protection was obtained by treatment with nifedipine, implicating Ca2+ entry through voltage-gated calcium channels as well as glutamate receptors in potentiating the toxicity of mutant SOD-1 in motor neurons. Dramatic neuroprotection was obtained by coexpressing the calcium-binding protein calbindin-D28k but not by increasing intracellular glutathione levels or treatment with the free radical spin trap agent, N-tert-butyl-alpha-phenylnitrone. Thus, generalized oxidative stress could have contributed in only a minor way to death of motor neurons expressing the mutant SOD-1. These studies demonstrated that the toxicity of these mutants is calcium-dependent and provide direct evidence that calcium entry during neurotransmission, coupled with deficiency of cytosolic calcium-binding proteins, is a major factor in the preferential vulnerability of motor neurons to disease.

All-fiber optical add-drop multiplexer based on a selective fused coupler and a single fiber bragg grating

We demonstrate a novel fiber add-drop multiplexer based on a selective fused coupler consisting of a twin-core fiber and a standard telecommunication fiber and a single fiber Bragg grating. Loss as low as ~1.1 dB for the added and dropped channel is demonstrated with a potential to be as low as ~0.4 dB. Better than 30-dB isolation is also achieved between the dropped and added channels. The device is based on well-developed fused coupler and Bragg grating technology. Most importantly, the method is noninterferometric, which means it does not need critical alignment or trimming. The fused coupler and grating are completely decoupled and can be made separately.

Study on oxygen supply and protection of bone marrow in acute radiation injured mice

After irradiated by 8 Gy 60Co gamma-ray, mice were intraperitoneally injected immediately with 0.2 ml 100% compound blood-activating soup twice a day for 10 days. The in situ ulnar bone marrow partial pressure of oxygen (PbO2) was determined in vivo before, during and after irradiation respectively. The bone marrow sections in the same part were observed. Our results showed that the normal murine ulnar PbO2 was 12.72 +/- 1.05 kPa. During irradiation, the level of PbO2 decreased to 10.78 +/- 1.17 kPa (P < 0.001). And 3 days after irradiation, PbO2 decreased to 9.75 +/- 0.52 kPa, suggesting that the commonly used "blood-activating and stasis-eliminating" Chinese drugs could promote the rehabilitation and proliferation of bone marrow microvessels in the acute radiation injured mice, expand their areas, increase the oxygen supply of bone marrow microenvironment, thereby leading to PbO2 much higher increase than that of control group. It is also helpful in the proliferation and rehabilitation of hematopoietic cells.

Fabrication of high-rejection low-loss single-passband filters in cladding depressed fiber by the chirped-grating concatenation method

High-rejection-low-loss single-passband filters have been successfully fabricated by the chirped-grating concatenation method in a cladding depressed fiber. The enhanced photosensitivity, the enlarged bandgap between the Bragg resonance and the cladding modes, and the effective suppression of the cladding-mode outcoupling of the cladding depressed fiber permitted what is to our knowledge the first achievement of an ~1-dB loss in the passband and 50-dB rejection for a 50-nm-wide stop band covering the entire amplified spontaneous emission spectral range of an Er-doped fiber amplifier.

Detection of Mycoplasma salivarium and Mycoplasma fermentans in synovial fluids of temporomandibular joints of patients with disorders in the joints

Thirty-six synovial fluid samples of temporomandibular joints were obtained from 33 patients with pain and anterior disk displacement (closed lock) in the joints. DNAs were prepared from the samples and amplified by a PCR-based assay specific for Mycoplasma salivarium or Mycoplasma fermentans. Of the 36 samples, five (14%), three (8%), and 19 (53%) were positive for M. salivarium, M. fermentans and both, respectively.

High-energy single-transverse-mode Q-switched fiber laser based on a multimode large-mode-area erbium-doped fiber

We demonstrate that appropriately designed doped multimode fibers provide robust single-mode output when used within a fiber laser cavity. Using a novel large-mode-area fiber, we demonstrate what we believe to be record single-mode (M(2) <1.2) pulse energies of >0.5 mJ from a Q -switched fiber laser and even higher pulse energies (as high as 0.85 mJ) with slightly compromised spatial-mode quality (M(2)<2.0) . This approach offers significant scope for extending the range of single-mode output powers and energies that are achievable from fiber-laser-amplifier systems.

Accurate tuning of mismatched twin-core fiber filters

We have demonstrated a reproducible and accurate way of tuning the coupling wavelength of a mismatched twin-core filter. This method allows high quality all-fiber filters to be implemented with low loss at any desired wavelength over a range of few hundred nanometers from the same fiber. An ~500-nm tuning range is demonstrated, limited only by the measurement setup and not by the technique itself. Highly accurate control of the filtering wavelength in combination with control of filtering strength by adjustment of the length of the twin-core fibers allows complex filter profiles to be implemented by cascading of several different filters. These filters are also very stable to a change in temperature (~0.26 nm/100 degrees C at 1.55 microm) and strain (less than 0.3 nm/mstrain at 1.55 microm), permitting easy packaging.

Coupling characteristics of cladding modes in tilted optical fiber bragg gratings

We have studied both theoretically and experimentally the effect of grating tilting on the coupling between the fundamental core mode and the cladding modes in an optical fiber Bragg grating. The coupling is shown to be very sensitive on the tilting angle. It is also shown that tilting angle has to be minimized in fibers with designs to suppress the coupling between the fundamental core mode and the cladding modes. We have also studied the single, strong loss peak accompanying the Bragg reflection peak in depressed-cladding fibers, thus showing a good agreement between behavior that is measured and that is predicted theoretically.

[Aberrant expression of immunoglobulin germline gene C mu in leukemias]

OBJECTIVE

To investigate the significance of immunoglobulin germline gene C mu expression in leukemias.

METHODS

Immunoglobulin germline gene C mu transcripts in 63 bone marrow samples from 59 leukemia patients were examined by RT-PCR.

RESULTS

Germline C mu transcripts could be identified in 17 of 26 AML, 9 of 12 ALL, 4 CML-BC and 2 CLL patients. HLA-DR was expressed in 80% C mu(+) patients and in 92.9% C mu(+) AML patients. In 10 normal bone marrow or peripheral blood samples C mu transcripts were undetectable.

CONCLUSION

Leukemogenesis in most acute leukemia may originate from the common progenitors of early B-lymphoid and myeloid cells.

A novel response to dioxin. Induction of ecto-ATPase gene expression

We used differential display to discover a new gene that the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) regulates in mouse hepatoma cells. Its predicted amino acid sequence suggests that the gene encodes an ecto-ATPase that contains multiple glycosylation sites, conserved cysteine residues, and apyrase conserved regions. cDNA expression experiments in mouse hepatoma cells confirm that the new gene encodes an ecto-ATPase. Wild-type mouse hepatoma cells contain both constitutive and TCDD-inducible ecto-ATPase activity. Induction of ecto-ATPase gene expression by TCDD is direct and occurs at the transcriptional level. Studies in mutant hepatoma cells indicate that induction requires both the aromatic hydrocarbon receptor (AhR) and the AhR nuclear translocator (Arnt). Furthermore, induction requires AhR's transactivation domain, but not that of Arnt. Our findings reveal new aspects of dioxin's biological effects and TCDD-dependent gene regulation.

A pencil-beam photon dose algorithm for stereotactic radiosurgery using a miniature multileaf collimator

A computer-controlled miniature multileaf collimator (MMLC) with 4 mm leaf width and a maximum field size of 6 cm X 6 cm has been designed as a tertiary beam-shaping device for linac-based stereotactic radiosurgery. The purpose of this study is to develop an accurate and efficient dose calculation model for use with the MMLC. A pencil-beam based algorithm using a sum of three Gaussian kernels was developed to model the off-axis ratio of MMLC fields. Because the kernel integration over a rectangular field can be solved in closed form, dose to any point from an arbitrary MMLC field can be calculated efficiently by summing dose contribution from a set of rectangular apertures and transmission blocks that model individual leaf openings or leaf transmissions. The model uses an effective rectangular field and equivalent square method for determination of depth dose and dose output. Results showed that the calculated percentage depth dose was within 1% and output factor was within 1.5% of measured data. The parameters of the pencil beam kernels were extracted by fitting measured off-axis profiles for a few field sizes at a few depths. The accuracy of the calculated off-axis ratio was tested by comparison with measured data for a number of MMLC fields. The algorithm was shown to be accurate to within 1.5% or 1 mm for off-axis ratios. The algorithm computes at a speed of 34,600 data points per second on a DEC Alpha server model 2000/433 (Digital Equipment Corp., Maynard, MA), which is about 15 times faster than a Clarkson-type summation method.

[Relationship between risk-taking behavior and knowledge for HIV infection among young men in Longchuan, Yunnan of China]

OBJECTIVE

To study the relationship between characteristics of risk-taking behavior and knowledge level of HIV infection/AIDS and risk perception of HIV infection among young men in an AIDS epidemic area.

METHODS

A cross-sectional survey was carried out among young men aged 18-29 years in 82 villages in Longchuan, Yunnan, China in 1994. Their demographic and behavioral information and knowledge level of AIDS were collected by interviewer administered anonymous questionnaire.

RESULTS

A total of 1,548 subjects were interviewed and 433 were drug abusers, including 192 intravenous users with 73% of them sharing syringes with others. Drug abusers were four times more likely to have pre-/extra-marital sex than non-users. More than half of the interviewees scored zero in HIV/AIDS knowledge.

CONCLUSION

Factors predisposing spread of HIV infection were common in the local young men. It is recommended that intervention be implemented as soon as possible to prevent HIV infection and AIDS.

[Treatment of arteriovenous malformation by linear accelerator radiosurgery]

OBJECTIVE

To summarize the effectiveness of radiosurgery for cerebral arteriovenous malformations (AVMs).

METHOD

We treated with linear accelerator radiosurgery 17 patients harboring AVMs in the brain. 15 AVMs were located supratentorially and others infratentorially. All the patients were treated with single fraction. The doses at AVM margin were 15 to 30 Gy.

RESULT

AVMs disappeared in 13 of the 17 patients, reduced in 3 and unchanged in only 1 at 2 year follow up. Vasogenic edema observed in 2 patients, their neurologic deficits were all improved with steroid.

CONCLUSION

Linear accelerator radiosurgery is effective in dealing with cerebral AVMs. It provides with a new means of treatment for AVMs which can't be effectively treated with microsurgery and embolization.

Transformation-sensitive changes in expression, localization, and phosphorylation of adducins in renal proximal tubule epithelial cells

Adducins are cytoskeletal proteins that facilitate interactions between spectrin and actin to form the subcortical membrane skeleton. We recently determined that alpha- and gamma-adducins are among a group of PKC substrates that we have designated "STICKS" (substrates that interact with C-kinase). To study the role of adducins and their regulation by protein kinase C (PKC) in carcinogenesis, we compared the content, localization, and phosphorylation of alpha- and gamma-adducins in primary renal proximal tubule epithelial (RPTE) cells and oncogene-altered derivative lines. RPTE cells expressing adenovirus E1A are immortalized but not transformed, whereas RPTE cells expressing SV40 large T antigen are transformed. Phosphorylation of adducins was monitored with a phosphorylation state-specific antibody directed toward the PKC phosphorylation site on adducins. Basal levels of phospho-alpha-adducin were relatively low in growing and confluent primary RPTE cells; however, basal levels of phosphoadducins relative to total adducins were increased in E1A-RPTE and SV40-RPTE cells. Phorbol esters stimulated alpha-adducin phosphorylation to a greater extent in primary cells than in oncogene-altered cells, possibly because of the already high basal levels of phosphorylation in those cells. Phosphorylated adducins were preferentially recovered in the soluble fraction, indicating that PKC phosphorylation either directly or indirectly influences the subcellular location and functions of adducins in regulating membrane skeleton structure. Thus, these studies provide evidence for increased endogenous PKC activity in oncogene-altered cells and suggest that the increased activity directly influences cytoskeletal organization by phosphorylating regulatory proteins, such as the adducins.

[Effect of ligustrazine on CD34 antigen expression of bone marrow cells in immune-mediated aplastic anemia mice]

OBJECTIVE

To explore the effect of ligustrazine on CD34 antigen expression of bone marrow cells in immune-mediated aplastic anemia (AA) mice.

METHODS

The model of immune aplastic anemia mice was induced by means of 6.0 Gy60Co gamma-ray irradiation and lymphocyte infusion through tail vein. The mice were divided into 3 groups: the normal group, the AA control group and the ligustrazine group. Mice of the ligustrazine group were fed by 4 mg of ligustrazine injection twice a day by gastrogavage. On the 10th day, CD34 antigen expression intensity of bone marrow cell membrane was measured by flow cytometer analysis system.

RESULTS

CD34 antigen expression intensity of ligustrazine group was 77.6 +/- 6.5, with no statistic difference from that in the normal group (80.0 +/- 2.6), while that of the control group was much higher (68.6 +/- 4.5, P < 0.05).

CONCLUSIONS

Ligustrazine could promote proliferation of stem and progenitor cell of AA mice through influencing on bone marrow micro-environment so as to increase the CD34 antigen expression of bone marrow cells.

Ultrastructural observation on spermatocytogenesis in Taeniid cestodes

AIM

To study the spermatocytogenesis of taeniid cestodes at the ultrastructural leaves.

METHODS

Transmission electron microscopy.

RESULTS

The ultrastructural observation on spermatocytogenesis in Taenia solium, T. saginata and T. pisiformis were made by TEM. Two types of spermatogonia; type A and B, as well as the supporting cells surrounding the peripheral of spermatogonia are recognized. The type A spermatogonia are stem cells and the type B are mother cells which produce 16 primary spermatocytes by mitosis for 4 times with the cells unseparated. The primary spermatocytes are characterized by the ribosome masses in the cytoplasm. 32 secondary spermatocytes arranged in roselike were produced by reductive division of primary spermatocytes. The secondary spermatocytes become the spermatid quickly by short time development.

CONCLUSION

The dividing mode of spermatogonia in Taeniid cestodes is mitosis with cells unseparated.

[Effect of HE-NE laser acupuncture on the spleen in rats]

The splenic sinuses, lymphocytes and antigen presenting cells in the spleen of rat stimulated by He-Ne laser acupuncture were observed by using TEM to investigate the ultrastructural changes of them. The width of endothelial interstice was increased, hence a lot of blood cells oozed out of the splenic sinuses. There were numerous activated T cells which contained abundant mitochondria and ribosome in the periarterial lymphatic sheaths. The B cells were gradually differentiated into large lymphocytes, immature and mature plasmatic cells with a lot of endoplasmic reticula. They were prominently increased in the splenic nodules. The macrophages had short processes with numerous folds and microvilli and tended to neighboring lymphocytes. The nucleus pores were increased. There were a lot of vacuoles, phagosome and mitochondria were closed to macrophages and lymphocytes. In conclusion the activities of the cellular immunity and humoral immunity were enhanced by laser.