Visual pathways involved in fear conditioning measured with fear-potentiated startle: behavioral and anatomic studies

Visual pathways to the amygdala, a brain structure critical for classical fear conditioning, were investigated. Conditioned fear was measured in rats as increased acoustic startle amplitude in the presence versus absence of a light or an odor paired previously with foot shock (fear-potentiated startle). Post-training lesions of both the lateral geniculate body (LG) and lateral posterior nucleus (LP) of the thalamus together, but not lesions of LG or LP alone, completely blocked the expression of fear-potentiated startle to a visual conditioned stimulus (CS) but not to an olfactory CS. These lesions also did not block contextual fear conditioning using startle or freezing as measures. Local infusion of 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f] quinoxaline-7-sulfonamide disodium, an AMPA antagonist, into the visual thalamus immediately before testing also blocked fear-potentiated startle to a visual CS, suggesting that the lesion effects were not attributable to damage of fibers of passage. Iontophoretic injections into the LP of the anterograde tracer biotinylated dextran amine resulted in heavy anterograde labeling in two amygdala-fugal cortical areas: area TE2 and dorsal perirhinal cortex (PR), and moderate labeling in the lateral amygdaloid nucleus (L). These results suggest that, during classical fear conditioning, a visual stimulus can be transmitted to the amygdala via either lemniscal (i.e., LG --> V1, V2 --> TE2/PR) or non-lemniscal (i.e., LP --> V2, TE2/PR) thalamo-cortico-amygdala pathways, or direct thalamo-amygdala (i.e., LP --> L) projections.

Hemodynamics and the focal origin of atherosclerosis: a spatial approach to endothelial structure, gene expression, and function

Atherosclerosis originates at predictable focal and regional sites that are associated with complex flow disturbances and flow separations in large arteries. The spatial relationships associated with hemodynamic shear stress forces acting on the endothelial monolayer are considered in experiments that model regions susceptible to atherosclerosis (flow disturbance) and resistant to atherosclerosis (undisturbed flow). Flow disturbance in vitro induced differential expression at the single gene level as illustrated for the intercellular communication gene and protein, connexin 43. Transcription profiles of individual endothelial cells isolated from both disturbed and undisturbed flow regions exhibited more expression heterogeneity in disturbed than in undisturbed flow. We propose that within highly heterogeneous populations of endothelial cells located in disturbed flow regions, proatherosclerotic gene expression may occur within the range of expression profiles induced by the local hemodynamics. These may be sites of initiation of focal atherosclerosis. Mechanisms are proposed to account for heterogeneous endothelial responses to shear stress by reference to the decentralized model of endothelial mechanotransduction. Length scales ranging from centimeters to nanometers are useful in describing regional, single cell, and intracellular mechanotransduction mechanisms.

Leukocyte integrin Mac-1 recruits toll/interleukin-1 receptor superfamily signaling intermediates to modulate NF-kappaB activity

The leukocyte integrin Mac-1 (alphaMbeta2, CD11b/CD18) regulates important cell functions in inflammation, including adhesion, phagocytosis, and oxidative burst. Deficiency of Mac-1 reduces vessel wall inflammation and neointimal thickening after murine carotid artery injury. Although Mac-1 has been implicated in modulating AP-1 and NF-kappaB activity, the signal transduction pathways involved are undefined. cDNA array analysis of Mac-1-clustered compared with -nonclustered monocytic THP-1 cells showed increased expression of the signal transducer TRAF6 (TNF receptor-associated factor 6), leading us to consider the possibility that Mac-1 used a Toll/IL-1 receptor family-like signaling pathway. Mac-1-dependent activation of NF-kappaB was potentiated by wild-type, and attenuated by dominant negative, TRAF6- and TGF-beta-activated kinase (TAK1) constructs. IRAK1 (IL-1 receptor associated kinase), a kinase immediately upstream of TRAF6, coimmunoprecipitated with Mac-1. Taken together, these observations indicate that Mac-1 recruits a Toll/IL-1 receptor family-like cascade to modulate NF-kappaB activity. This represents a new pathway for integrin-dependent modulation of gene expression.

Catalysis of the electro-oxidation of carbon monoxide by cobalt octaethylporphyrin

The electro-oxidation of cobalt (II) octaethylporphyrin adsorbed on graphite electrodes, Co(II)(OEP)(ads') to Co(III)(OEP)(ads)(+), in the presence of aqueous solutions of CO leads to catalytic oxidation of CO to CO(2). No such oxidation occurs with Co(II)(OEP) and CO dissolved in nonaqueous solvents. Coordination of the CO to Co(III)(OEP)(+) is the first step in the catalytic mechanism. Nucleophilic attack on the coordinated CO by H(2)O is the probable rate-limiting step in the catalytic oxidation. A pseudo first-order rate constant of 0.3 s(-1) was estimated for this reaction.

HIV gp120 V(1)/V(2) and C(2)-V(3) domains glycoprotein compatibility is required for viral replication

The envelope gene, especially the V(3) region, of HIV-1 has been shown to be a principal determinant of cell tropism, replication and cytopathogenicity of the virus. In addition, the V(1)/V(2) region of the envelope gene has been found to be an important factor in cell tropism. We examined the compatibility between the V(1)/V(2) and C(2)-V(3) domains of HIV-1 gp120 in different combinations on viral replication by using envelope recombinants between ME1 and ME46, two infectious molecular clones with diverse biologic activity longitudinally isolated from one seropositive subject. Our data demonstrate that a proper interaction between the regions of V(1)/V(2)and C(2) is essential for viral infection and hence replication. Sequence analysis and subsequent site directed mutagenesis study indicate that the pattern of potential envelope N-glycosylation in the V(1)/V(2) and C(2)-V(3) regions may be the determining factor in such interaction between these two regions. It is possible that improper N-glycosylation sites while not affecting virus assembly, can influence through steric hindrance the conformational change of the V(3) region that is required for the co-receptor attachment and hence the viral infectivity.

[The possibility to establish the scale of quality of life (QOL) fit for Chinese lung cancer patients]

BACKGROUND

To establish and validate the scale of quality of life( QOL) fit for Chinese lung cancer patients.

METHODS

By reviewing the other scales of QOL, we designed the new scale of QOL which include 5 factors with totally 65 items. It referred to biological and psychosocial aspects. Three hundred fifty-five patients with lung cancer were reviewed. The scores were compared with KPS by different group mean t-test.

RESULTS

Patients and doctors could understand the contents of this scale, except for 2 patients who only accepted elementary education. Significant differencewas observed in total score, gender and emotional well-being among patients in different stage( P < 0. 05) . The functional well-being of stage IV patients was worse than that of other stage patients( P < 0. 05) . The emotional well-being of female patients was worse than that of male patients( P < 0. 05) .

CONCLUSIONS

This scale is reliable, valid and capable in clinics.

[Clinical study on the efficacy of tranexamic acid in reducing postpartum blood lose: a randomized, comparative, multicenter trial]

OBJECTIVE

To study the efficacy and safety of Transamin (tranexamic acid) in reducing postpartum blood loss.

METHODS

Four hundred primipara with term singleton pregnancy, vertex presentation, spontaneous delivery were enrolled. Ten U Oxytocin was injected intravenously immediately after the delivery of fetal shoulders in the second stage of labor. Then all the puerperants were randomly assigned to 4 groups. Group I (n = 94): Transamin 1.0 g was injected i.v.; Group lI (n = 92): Transamin 0.5 g i.v.; Group III (n = 92): aminomethylbenzoic acid 0.5 g i.v. was given; Group IV (n = 87): no treatment. Vaginal bleeding was precisely collected, and examined immediately after the expulsion of placenta and from placenta expulsion till 2 hours after delivery. The amount of blood loss was measured by both methods of weight and volume.

RESULTS

There were no significant differences of blood loss immediately after the expulsion of placenta among the 4 groups (P > 0.05). For the average blood loss at 2 hour postpartum, it was 129.7 ml, 133.9 ml, 168.5 ml and 178.2 ml for group I, II, II and IV respectively, while the total blood loss for the 4 groups was 243.3 ml, 242.9 ml, 308.1 ml, and 314.8 ml respectively. The average blood loss of group I and II was significantly less than group III and IV (P < 0.01), however, there was no significant difference between group I and group II (P > 0.05). The occurrences of postpartum hemorrhage (blood lose > or = 400 ml) were 6.4%, 13.3%, 20.7% and 25.3% for group I, II, III and IV respectively. There was no major adverse effects appeared.

CONCLUSIONS

Transamin is efficient and safe in reducing the postpartum blood loss. 1.0 g of Transamin has the best efficacy, and 0.5 g of Transamin followed.

Monoaminergic innervation of the macaque extended amygdala

The extended amygdala is a group of structures including the central and medial amygdaloid nuclei, bed nucleus of the stria terminalis, and sublenticular substantia innominata. This group of structures is thought to be important in a variety of psychiatric disorders, many of which are linked in one way or another to monoamines and their transporters. However, not much is known about the distribution of these molecules in the primate extended amygdala. Thus, we mapped the distribution of fibers immunoreactive for tyrosine hydroxylase, dopamine beta-hydroxylase, serotonin, dopamine transporter, and serotonin transporter in the brains of macaque monkeys. Tyrosine hydroxylase-, serotonin-, and serotonin transporter-immunoreactive fibers were found in highest concentrations in the lateral division of the central nucleus and lateral dorsal part of the bed nucleus of the stria terminalis. Dopamine beta-hydroxylase-immunoreactive fibers were found in the highest concentration in the lateral ventral bed nucleus of the stria terminalis. Dopamine transporter-immunoreactive fibers were found in the highest concentrations in the lateral juxtacapsular and lateral dorsal capsular subnuclei of the bed nucleus and lateral capsular subnucleus of the central amygdaloid nucleus, though in much lower amounts than was present in the striatum. These results suggest prominent roles for these transmitters, particularly in the lateral dorsal bed nucleus and lateral part of the central nucleus. The relative absence of dopamine transporter in the extended amygdala suggests that this transmitter acts more through volume transmission while serotonin, which is generally accompanied by proportionate amounts of transporter, may act more like a classical neurotransmitter. In addition, the finding of heavy concentrations of dopamine- and serotonin-immunoreactive fibers in the lateral central nucleus and lateral dorsal bed nucleus lends further support to the idea of these areas as parallels in some respects to the striatum.

[Gene dispersal risk of transgenic plants]

Gene flow is a key problem and top topic in risk assessment and management of transgenic plants. Five major study areas of gene dispersal in transgenic plants were reviewed in this paper, which include gene flow from transgenic plant to its wild species, characteristics of gene flow based on pollen, methods of doing experiment and risk assessment for gene flow, safety standards of risk assessment of transgenic plants, and long-term ecological impact of gene flow in the future. Some areas needed to be studied further were also proposed.

The interaction of azide with polyphenol oxidase II from tobacco

Spectroscopy studies of absorption and circular dichroism of native PPO II and azide PPO II complex demonstrate two new absorptions at 375 nm and 500 nm after azide's binding with PPO II, which are assigned as the terminal azide to copper charge transfer transitions II(o)nb-to-copper and II(v)nb-to-copper charge transfer transitions respectively. FT-IR spectra also demonstrate that the azide binds in terminal geometry with one of type-3 coppers. The interaction between azide and PPO II is discussed. One terminal azide's binding with one type-3 copper improves the activity of PPO II and the other three azides' further binding in terminal geometry with the type-3 coppers decreases the activity. We theorize that steric hindrance of azides makes oxygen difficult to bind in the active site.

Photodynamic Therapy With Motexafin Lutetium Induces Redox-Sensitive Apoptosis of Vascular Cells

Abstract —Motexafin lutetium is a photosensitizer that accumulates in atherosclerotic plaque and, after activation by far-red light, produces cytotoxic singlet oxygen. The combination of photosensitizer and illumination, known as photodynamic therapy (PDT), has been shown to reduce atheroma formation in animal models and is under clinical investigation. However, the effects of PDT with motexafin lutetium on isolated vascular cells are unknown. This study was designed to characterize the effects of PDT on vascular cell viability and to define the cell-death pathway for this agent. Fluorescence microscopy of RAW macrophages and human vascular smooth muscle cells revealed time-dependent uptake of motexafin lutetium. Illumination of motexafin lutetium–loaded cells with 732-nm light (2 J/cm 2 ) impaired cellular viability and growth (IC 50 5 to 20 μmol/L). Depletion of intracellular glutathione potentiated ( P =0.035) and the addition of antioxidant N -acetylcysteine attenuated ( P =0.002) cell death, suggesting that the intracellular redox state influences motexafin lutetium action. PDT was associated with the loss of mitochondrial membrane potential, mitochondrial release of cytochrome c , and caspase activation. PDT promoted phosphatidylserine externalization and induced apoptotic DNA fragmentation, with the number of apoptotic cells increasing from 7±2% to 34±3% of total cells. Reducing plaque cellularity by the induction of apoptosis may be one mechanism by which PDT reduces plaque burden, possibly modulates plaque vulnerability, and inhibits restenosis in vivo.

Long-term memory is facilitated by cAMP response element-binding protein overexpression in the amygdala

At least two temporally and mechanistically distinct forms of memory are conserved across many species: short-term memory that persists minutes to hours after training and long-term memory (LTM) that persists days or longer. In general, repeated training trials presented with intervening rest intervals (spaced training) is more effective than massed training (the same number of training trials presented with no or short intervening rest intervals) in producing LTM. LTM requires de novo protein synthesis, and cAMP response element-binding protein (CREB) may be one of the transcription factors regulating the synthesis of new proteins necessary for the formation of LTM. Here we show that rats given massed fear conditioning training show no or weak LTM, as measured by fear-potentiated startle, compared with rats given the same amount of training but presented in a spaced manner. Increasing CREB levels specifically in the basolateral amygdala via viral vector-mediated gene transfer significantly increases LTM after massed fear training. The enhancing effect of CREB overexpression on LTM formation is shown to be specific in terms of biochemistry, anatomy, time course, and the training procedure used. These results suggest that CREB activity in the amygdala serves as a molecular switch for the formation of LTM in fear conditioning.

Drug delivery systems employing 1,6-elimination: releasable poly(ethylene glycol) conjugates of proteins

Using lysozyme as a representative protein substrate that loses its activity when PEGylation takes place on the epsilon-amino group of lysine residues, various amounts of a novel releasable PEG linker (rPEG) were conjugated to the protein. rPEG-lysozyme conjugates were relatively stable in pH 7.4 buffer for over 24 h. However, regeneration of native protein from the rPEG conjugates occurred in a predictable manner during incubation in high pH buffer or rat plasma, as demonstrated by enzymatic activity and structural characterization. The rates of regeneration were also correlated with PEG number: native lysozyme was released more rapidly from the monosubstituted conjugate than from the disubstituted conjugate, suggesting possible steric hindrance to the approach of cleaving enzymes. Recovery of normal activity and structure for the regenerated native lysozyme was shown by a variety of assays.

Fast-track cardiac anesthesia: a comparison of remifentanil plus intrathecal morphine with sufentanil in a desflurane-based anesthetic

OBJECTIVE

To compare the effects of an intravenous remifentanil infusion plus intrathecal morphine with intravenous sufentanil infusion with respect to intraoperative hemodynamic variables, extubation times, and recovery profiles when administered as part of a desflurane-based fast-track anesthetic regimen for cardiac surgery.

DESIGN

A prospective, randomized, nonblinded study.

SETTING

University hospital.

PARTICIPANTS

Forty patients undergoing elective primary coronary artery bypass graft, aortic valve replacement, or mitral valve replacement surgery.

INTERVENTIONS

After a standardized anesthetic induction, anesthesia was maintained with a remifentanil infusion, 0.1 microg/kg/min, and desflurane, 3% to 10%, inspired (group I, n = 20) or a sufentanil infusion, 0.3 microg/kg/h, and desflurane, 3% to 10%, inspired (group II, n = 20). Patients receiving remifentanil were administered intrathecal morphine, 8 microg/ kg, for postoperative analgesia.

MEASUREMENTS AND MAIN RESULTS

Both anesthetic regimens provided comparable intraoperative hemodynamic stability and similar recovery profiles, with extubation times of 5.1 +/- 4.3 hours (group I) and 5.8 +/- 6.7 hours (group II).

CONCLUSIONS

Use of remifentanil in combination with intrathecal morphine did not facilitate earlier tracheal extubation or improve intraoperative hemodynamic stability compared with sufentanil alone for fast-track cardiac anesthesia.

Synthesis of 6H-indolo[2,3-b][1,6]naphthyridines and related compounds as the 5-Aza analogues of ellipticine alkaloids

Treatment of 2-(1-alkynyl)phenyl isocyanates 6 with the iminophosphorane 14 produced in situ the benzoenynyl carbodiimides 15. Thermolysis of 15 under refluxing p-xylene furnished the 6H-indolo[2,3-b][1,6]naphthyridines 5, which could be regarded as the 5-aza analogues of ellipticine alkaloids. Similarly, condensation of 6 with the iminophosphorane 20 led to the formation of the 6H-indolo[2,3-b][1,5]naphthyridines 25 as the major isomer and the 10H- indolo[2,3-b][1,7]naphthyridines 26 as the minor isomer. The indolonaphthyridines 32, 33, and 34 having a methoxyl substituent were likewise synthesized. Treatment of the diisocyanate 43 with 2 equiv of the iminophosphorane 7 furnished 45 having two indoloquinoline units incorporated in a seven-fused-ring system.

[The first discovery of endemic Lyme disease in Shandong province]

OBJECTIVE

To investigate the endemic area of Lyme disease in Shandong province.

METHODS

An investigation on endemic Lyme disease was conducted by means of serological and etiological methods in Shandong province from 1992 to 1999.

RESULTS

Of 1919 forestry residents, 120 residents had a significant antibody titer against Borolo burgdorferi strain B(31). The prevalance rate of Lyme disease was 6.25%. Haemaphysalis longicornis was a prevailing species of Ixodidae in the region. Spirochetes were observed in the midguts of 50 H. longicornis in this area by direct fluorescence antibody method. The overall positive rate was 12.0% (6/50). Two strains (TSH(1), TSH(3)) of spirochetes were isolated from H. longicornis. Both TSH(1) and TSH(3) were positively responded to McAb H(5332) and H(9724), but negatively to H(6831). Spirochetes were observed in the kidneys of 46 Rattus in this area by direct fluorescence antibody method with a positive rate of 13.26% (6/46).

CONCLUSION

It was the first time that the mountainous areas in Shandong province was confirmed endemic areas of Lyme disease.

Fast-track cardiac anesthesia: use of remifentanil combined with intrathecal morphine as an alternative to sufentanil during desflurane anesthesia

The purpose of this cardiac fast-track study was to evaluate the use of remifentanil (R) combined with intrathecal (IT) morphine as an alternative to sufentanil (S) during desflurane anesthesia with respect to postoperative pain control. Prior to entering the operating room, patients in the R group (n = 20) received morphine, 8 microg/kg IT. Anesthesia was induced using a standardized anesthetic technique in all patients. In the R group, anesthesia was maintained with R, 0.1 microg. kg(-1). min(-1) in combination with desflurane 3-10%. In the S group (n = 20), patients received S 0.3 microg. kg(-1). h(-1) and desflurane 3-10%. There were no differences between the two groups with respect to time from arrival in the intensive care unit to tracheal extubation (5.1 +/- 4.3 h vs 5.8 +/- 6.7 h for R and S groups, respectively). After extubation, patients in the R group had significantly lower visual analog pain scores, reduced patient-controlled analgesic requirements, and greater satisfaction with their perioperative pain management, compared with patients in the S group. We conclude that R combined with IT morphine provided superior pain control after cardiac surgery compared with a S-based general anesthetic technique.

IMPLICATIONS

As part of a cardiac fast-tracking program involving desflurane anesthesia, the use of intrathecal morphine in combination with a remifentanil infusion provided improved postoperative pain control, compared with IV sufentanil alone.

[Expression of leukemia inhibitory factor in human decidua]

OBJECTIVE

To study the expression and localization of leukemia inhibitory factor (LIF) in human first trimester decidual.

METHOD

By immunohistochemical analysis and in situ hybridization, the LIF mRNA and protein expression were observed in 16 cases of human decidua.

RESULTS

LIF mRNA and protein expressions were observed in all decidual specimens, the glanduar epithelium showed higher LIF expression than in stromal cells.

CONCLUSION

Expression of LIF in human decidua may contribute to embryo implantation, maintenance of placental functions and embryonic growth promation.

Bilateral pallidotomy for treatment of idiopathic Parkinson's disease

OBJECTIVE

To clarify the benefits and risks of patients undergoing bilateral posteroventral pallidotomy (BPVP) for patients with idiopathic Parkinson's disease (PD) and the differences between contemporaneous BPVP (CBPVP) and staged BPVP (SBPVP).

METHODS

Twenty patients underwent microelectrode-guided CBPVP and 26 SBPVP for bilateral PD symptoms. The data were retrospectively reviewed. Unified Parkinson's Disease Rating Scale (UPDRS) was used to evaluate the effects of these operations.

RESULTS

BPVP, either CBPVP or SBPVP, significantly improved patients' bilateral PD symptoms (P < 0.001). The improvement was consistently higher in "off" state than in "on" state. No statistical difference was observed in the improvement percentages of CBPVP, SBPVP1 and SBPVP2. CBPVP contributed greatly to L-dopa induced side effects (part IV). BPVP, SBPVP1, and SBPVP2 significantly improved cardinal parkinsonian signs but no difference was found among them. One patient after CBPVP developed hypophonia and swallowing problem, while 2 patients after SBPVP sustained hypophonia. These conditions were improved 3 months later.

CONCLUSIONS

BPVP may significantly improve bilateral signs of PD. It is safer than bilateral thalamotomy. CBPVP is applicable to some patients. BPVP may not cause mental impairment but shows a higher incidence rate of hypophonia. The practice of BPVP requires a refined surgical technique and a better understanding of pathophysiology of the basal ganglia.

Biometry of the fetal heart between 10 and 17 weeks of gestation

OBJECTIVES

Assessment of the dimensions of the cardiac chambers and the great arteries in the human fetus may be helpful in the prenatal diagnosis of congenital heart disease. The purpose of this prospective cross-sectional study was to compile normative data in fetal cardiac measurements in early pregnancy. The structure of the fetal heart was examined in 136 normal singleton fetuses between 10 and 17 weeks of gestation.

METHODS

The transversal heart diameter, both ventricular dimensions, interventricular septal thickness, heart area, heart circumference, thoracic diameter, thoracic circumference and thoracic area were measured in the four-chamber view during diastole. Diameters of the pulmonary trunk and ascending aorta were obtained in the short axis and long axis view during systole. Ultrasound examinations were performed with a 5.0-MHz transvaginal and/or transabdominal phased-array sector scanner.

RESULTS

The four-chamber view and the cross-over of the pulmonary artery and the aorta were adequately visualized in 44% of the fetuses at 10 weeks of gestation, in 75% at 11 weeks of gestation, in 93% at 12 weeks of gestation and in 100% of the fetuses at 13-17 weeks of gestation. Before 14 weeks of gestation transvaginal sonography was superior to the transabdominal sonography in visualization of the fetal heart and great arteries. After 14 weeks of gestation transabdominal sonography accurately demonstrated the structure of the fetal heart. The ratio of right and left ventricle (RV/LV) and the ratio of the pulmonary trunk and aorta (PT/AO) were constant during this period of gestation (approximately 1.00 and 1. 10, respectively). The ratio of the cardiac and thoracic area showed only a slight increase with advancing gestational age, but with significant correlation. The fetal heart rate showed a slow decrease from 167 to 150 bpm in this period of gestation. The transversal heart diameter, both ventricular dimensions, interventricular septal thickness, heart area, cardiothoracic diameter ratio, aortic diameter and the pulmonary trunk diameter showed a highly significant linear correlation to the gestational age and the biparietal diameter.

CONCLUSION

The advancing quality of ultrasound images allows fetal echocardiography in the first and early second trimester. Our normative data could be the basis of studying the development of cardiac structures in congenital heart disease and it might be helpful in the detection of some congenital heart defects in early pregnancy.

Deregulated c-myc expression in quiescent CHO cells induces target gene transcription and subsequent apoptotic phenotype

Human c-myc cDNA was fused with the hormone-binding domain (HBD) cDNA of murine estrogen receptor gene and the chimeric gene was introduced into the CHO cells. The fusion protein, c-MycER, becomes activated when the synthetic steroid, 4-hydroxy-tamoxifen (OHT), binds HBD. Activated c-MycER, likely c-Myc, can induce quiescent CHO cells reentry into S phase and subsequent cell death under serum-free condition. In addition, the expression of some proposed c-myc target genes such as ODC, MrDb, cad, rcc1 and rcl were found to increase upon OHT induction before S phase entry and apoptosis, indicating that these target genes are involved in cell cycle regulation and/or apoptosis control. However, the mutant D106-143c-MycER protein does not have above activities.

The Gelation of CO(2): A Sustainable Route to the Creation of Microcellular Materials

Compounds with strong thermodynamic affinity for carbon dioxide (CO(2)) have been designed and synthesized that dissolve in CO(2), then associate to form gels. Upon removal of the CO(2), these gels produced free-standing foams with cells with an average diameter smaller than 1 micrometer and a bulk density reduction of 97 percent relative to the parent material.

Hyposmotically activated chloride channels in cultured rabbit non-pigmented ciliary epithelial cells

1. We used whole-cell patch-clamp recording techniques and noise analysis of whole-cell current to investigate the properties of hyposmotic shock (HOS)-activated Cl- channels in SV40-transformed rabbit non-pigmented ciliary epithelial (NPCE) cells. 2. Under conditions designed to isolate Cl- currents, exposure of cells to hyposmotic external solution reversibly increased the whole-cell conductance. 3. The whole-cell current activated with a slow time course (> 15 min), exhibited outward rectification and was Cl- selective. 4. The disulphonic stilbene derivatives 4, 4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS, 0.5 mM), 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS, 0. 5 mM) and 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS, 0.5 mM) produced a voltage-sensitive block of HOS-activated Cl- current at depolarized potentials, whereas niflumic acid produced a voltage-independent block of the current. 5. Under Ca2+-free conditions, HOS stimulation still reversibly activated the Cl- current, but the amplitude of current was reduced and the time course of current activation was slower compared with control (P < 0. 05). 6. The non-specific kinase inhibitor H-7 (100 microM), upregulated HOS-activated Cl- current amplitude in all cells tested (P < 0.05). 7. Noise analysis of whole-cell Cl- current indicated that cell swelling activated a high density of small conductance Cl- channels (< 1 pS). 8. We conclude that HOS primarily activates a high density of volume-sensitive small conductance Cl- channels in rabbit NPCE cells, and that Ca2+ and phosphorylation are involved in channel regulation.

Prolonged circulating lives of single-chain Fv proteins conjugated with polyethylene glycol: a comparison of conjugation chemistries and compounds

The utility of single-chain Fv proteins as therapeutic agents would be substantially broadened if the circulating lives of these minimal antigen-binding polypeptides were both prolonged and adjustable. Poly(ethylene glycol) (PEG) bioconjugate derivatives of the model single-chain Fv, CC49/218 sFv, were constructed using six different linker chemistries that selectively conjugate either primary amines or carboxylic acid groups. Activated PEG polymers with molecular weights of 2000, 5000, 10 000, 12 000, and 20 000 were included in the sFv bioconjugate evaluation. Additionally, the influence of PEG conjugate geometry in branched PEG strands (U-PEG) and the effect of multimeric PEG-sFv bioconjugates on circulating life and affinity were examined. Although random and extensive PEG polymer conjugations have been achievable in highly active derivatives of the prototypical PEG-enzymes, PEGylation of CC49/218 sFv required stringent adjustment of reaction conditions in order to preserve antigen-binding affinity as measured in either mucin-specific or whole cell immunoassays. Purified bioconjugates with PEG:sFv ratios of 1:1 through 2:1 were identified as promising candidates which exhibit sFv affinity (K(d)) values within 2-fold of the unmodified sFv protein. Interestingly, PEG conjugation to carboxylic acid moieties, using a PEG-hydrazide chemistry, achieved significant activity retention in bioconjugates at a higher PEG:sFv ratio (5:1) than with any of the amine-reactive activated PEG polymers. Prolonged circulating life in mice was demonstrated for each of the PEG conjugates. An increase in PEG polymer length was found to be more effective for serum half-life extension than a corresponding increase in total PEG mass. For example, CC49/218 sFv conjugated to either one strand of PEG-20000, or four strands of PEG-5000, displayed about 20- or 14-fold increased serum half-life, respectively, relative to the unmodified sFv. The demonstrated suitability of established random conjugation chemistries for PEGylation of sFv proteins, in conjunction with innovative site-specific conjugation methods, indicates that production of a panoply of sFv proteins with both engineered affinity and tailored circulating life may now be achievable.

[Amplification of phytoplasma 16S rDNA from banana bunchy top disease, RFLP and sequence analysis of 16S rDNA fragment]

Extract DNA from banana plants with banana bunchy top disease and amplify the phytoplasma 16S rDNA fragment by nested PCR. The classification of the phytoplasma established on the basis of 16S rDNA restriction patterns was examined by performing a sequence analysis of 16S rDNA fragment. The RFLP pattern, sequence data and phylogenic tree showed that this phytoplasma should belong to Group I(Phytoplasma asteri).

[Cloning of 0-17.5 mu and sequencing of 0-4.8 mu of the lefe and DNA of the Ad7 vaccine strain left end]

OBJECTIVE

Cloning of 0-17.5 mu DNA fragment of adenovirus 7 vaccine strain and sequencing of 0-4.8 mu fragment (1,737 bp).

METHODS

Isolating and purifying Ad7 vaccine genome from the A549 cultured cells, putting 0.3-17.5 mu fragment into pAd7T plasmid, then sequencing the 0-4.8 mu fragment including inverted terminal repeats (ITR), packaging sequence and Ela region.

RESULTS

We obtained 0-17.5 mu fragment of Ad7 vaccine strain genome and sequenced its left terminal 1,737 bp. Sequence analysis showed that the Ad7 vaccine strain Ela region encodes 6,300, 24,000 and 28,000 proteins. Compared with equivalent region of Ad7 Gomen strain, they share the homology of the nucleotide sequence 98.9%, 97.3%, 97.5% and the homology of the deduced amino acid sequence 96.6%, 96.5%, and 96.9% respectively. When compared with Ad7 Grider strain, they share the homology of the nucleotide sequence 100%, 99.7%, 99.7% and the homology of the deduced amino acid sequence 100%, 99.1%, and 99.2% respectively.

CONCLUSION

The Ad7 vaccine strain left terminal 1,737 bp nucleotide sequence showed a high homology with corresponding region of Ad7 Gomen strain and Grider strain.

Cortical afferents to the extended amygdala

The projections of the cerebral cortex to the extended amygdala were studied in the rat using anterograde and retrograde tract-tracing techniques. Most cortical areas with strong projections to the extended amygdala preferentially targeted either the medial extended amygdala (including the medial amygdalar nucleus, ventromedial substantia innominata, and the medial part of the bed nucleus the stria terminalis) or the central extended amygdala (including the central amygdalar nucleus, dorsolateral substantia innominata, and the lateral part of the bed nucleus of the stria terminalis). Some cortical areas, however, had equal projections to both medial and central portions. The main areas projecting preferentially to the medial extended amygdala were the ventral subiculum, infralimbic cortex, ventral agranular insular area, and the rostral part of the ventrolateral entorhinal area. The main areas projecting preferentially to the central extended amygdala were the prefrontal cortex, viscerosensory and somatosensory portions of the insular cortex, and the amygdalopiriform transitional area. It is suggested that these cortical inputs may be important for cognitive, mnemonic, and affective aspects of emotional and motivated behavior.

The extended amygdala: are the central nucleus of the amygdala and the bed nucleus of the stria terminalis differentially involved in fear versus anxiety?

Although there is a close correspondence between fear and anxiety, and the study of fear in animals has been extremely valuable for understanding the neural basis of anxiety, it is also clear that a richer animal model of human anxiety disorders would include measures of both stimulus-specific fear and something less stimulus specific, more akin to anxiety. Patients with posttraumatic stress syndrome seem to show normal fear reactions but abnormal anxiety measured with the acoustic startle reflex. Studies in rats, also using the startle reflex, indicate that highly processed explicit cue information (lights, tones) activates the central nucleus of the amygdala, which projects to and modulates the acoustic startle pathway in the brain stem. Less explicit information, such as that produced by exposure to a threatening environment or by intraventricular administration of corticotropin-releasing hormone, may activate another part of the extended amygdala, the bed nucleus of the stria terminalis, which also projects to the startle pathway. Because this information may be less specific and of long duration, activation of the bed nucleus of the stria terminalis may mediate anxiety, whereas activation of the central nucleus of the amygdala may mediate stimulus-specific fear.

The intrinsic organization of the central extended amygdala

The central component of the extended amygdala (CEA) comprises the central amygdaloid nucleus (Ce), the dorsal substantia innominata (SI), and the bed nucleus of the stria terminalis (BNST). Anatomical studies have suggested the presence of an intrinsic system of GABAergic neurons that not only connects homologous subareas of the Ce, SI, and BNST but that also acts as an interface between sensory afferents and brain stem-projecting neurons. CEA outputs, with a few exceptions, arise from separate populations of neurons, but all, including GABAergic neurons themselves, are heavily innervated by GABAergic terminals. GABAergic neurons may serve to integrate output activity of the CEA, though GABAergic neurons form a heterogeneous population whose differential intrinsic connections appear related to their peptide content. Afferents from the dysgranular insular cortex and lateral parabrachial complex preferentially innervate GABAergic neurons, suggesting these neurons may also integrate afferent activity. Afferents from the basolateral amygdala (BL) appear to innervate both output neurons and intrinsic GABAergic neurons. Evidence will be presented to show that BL afferents form synaptic complexes with cortical, GABAergic, and TH-immunoreactive terminal boutons on GABAergic dendritic spines. These complexes may be a key element in control of CEA output activity.

Plasminogen is not required for neointima formation in a mouse model of vein graft stenosis

Recent studies of mice that lack plasminogen have identified a critical role for this zymogen in arterial remodeling. To permit the use of these (and other) genetically modified mice in the analysis of venous injury, we developed a model in which a patch cut from the external jugular vein of a mouse is grafted to repair a surgically created defect in its carotid artery. In wild-type mice, the venous graft showed initial endothelial denudation and formation of a neointima that progressively and reproducibly expanded in a manner analogous to human vein graft disease, albeit at an accelerated pace. This neointima occupied 37+/-4.6% of the vessel lumen at day 7 and 66+/-5.7% at day 20. The proliferative index of neointimal cells assessed by proliferating cell nuclear antigen staining was 50.6+/-3. 6% at day 7 and 15.2+/-2.0% at day 20. CD45-positive leukocytes and alpha-actin-positive smooth muscle cells accounted for 9.5+/-1.0% and 9.9+/-1.1% of intimal area at day 7, respectively, with the latter increasing to 40.9+/-2.6% at day 20. Collagen accounted for 6.8+/-0.7% of intimal area at day 7 and 20.7+/-1.8% at day 20. Surprisingly, even though arterial neointima formation due to electrostatic and immune-mediated injury is impaired in plasminogen -/- mice, in our study vein graft neointima formation in these mice was not significantly different from that in controls (70.9+/-6.4 versus 65.6+/-4.4% luminal occlusion, P=NS). Thus, plasmin proteolysis, although critical in extracellular matrix degradation and cellular migration after arterial injury, does not appear to be so important in vein graft neointima formation, perhaps because of the relative lack of structural barriers to cellular migration in the normal vein wall. This novel model of vein graft injury should be useful for further studies of differences in the response to injury of arterial and venous tissues.

[Construction of adenovirus 4 vector with deletion of 78.9-86 mu fragment and express of beta-galactosidase gene]

OBJECTIVE

To construct a human adenovirus type 4(Ad4) vector with partial deletion at E3 region (78.9-86 mu).

METHODS

Ad4 DNA was extracted from purified virus cultured in WI-38 cells. The essential fragment(71.3-100 mu) covering Ad4 E3 region was cloned and partial deletion of E3 region of this clone has been performed, generating plasmid pAd4 delta KS. Furthermore, a beta-galactosidase (beta-gal) gene flanked by CMV early promoter and SV40 poly A signal was inserted into pAd4 delta KS, resulting in pAd4c beta. This plasmid was cotransfected with Ad4 DNA, Bcl I A fragments into 293 cells, producing a non-defective recombinant Ad4 virus encoding B-gal.

RESULT

The results showed that the constructed recombinant virus could efficiently express the foreign gene, beta-gal.

CONCLUSION

Ad4 vector with a deletion of E3 region can be explored as a live vaccine for prevention of human infectious diseases.

Donor MHC and adhesion molecules in transplant arteriosclerosis

Transplant-associated arteriosclerosis remains an obstacle to long-term graft survival. To determine the contribution to transplant arteriosclerosis of MHC and adhesion molecules from cells of the donor vasculature, we allografted carotid artery loops from six mutant mouse strains into immunocompetent CBA/CaJ recipients. The donor mice were deficient in either MHC I molecules or MHC II molecules, both MHC I and MHC II molecules, the adhesion molecule P-selectin, intercellular adhesion molecule (ICAM)-1, or both P-selectin and ICAM-1. Donor arteries in which ICAM-1, MHC II, or both MHC I and MHC II were absent showed reductions in neointima formation of 52%, 33%, and 38%, respectively, due primarily to a reduction in smooth muscle cell (SMC) accumulation. In P-selectin-deficient donor arteries, neointima formation did not differ from that in controls. In donor arteries lacking both P-selectin and ICAM-1, the size of the neointima was similar to that in those lacking ICAM-1 alone. In contrast, neointima formation increased by 52% in MHC I-deficient donor arteries. The number of CD4-positive T cells increased by 2.8-fold in MHC I-deficient arteries, and that of alpha-actin-positive SMCs by twofold. These observations indicate that ICAM-1 and MHC II molecules expressed in the donor vessel wall may promote transplant-associated arteriosclerosis. MHC I molecules expressed in the donor may have a protective effect.

[Studies on the stability of sodium taurocholate in different media and in the course of sterilization]

OBJECTIVE

To investigate the stability of the main active constituent of snake gall sodium taurocholate, TCANa in 25% alcoholic solution and artificial gastric juice, and in the course of hot pressurized sterilization.

METHOD

The stability of the solution was predicted by an accelerated isothermal test, and the content of TCANa was determined by TLC-colorimetry.

RESULT

The half-time(t1/2) of TCANa in 25% alcoholic solution is 60.57 d at 25 degrees C, and in artificial gastric juice 11.37 d at 37 degrees C, the loss rate under the condition(115 degrees C, 30 min) of sterilization about 3%.

CONCLUSION

TCANa in 25% alcoholic solution is unstable. Therefore it is suggested that in order to raise the stability of TCANa the alcoholic concentration be increased and the solution be stored at temperatures below 0 degree C.

[Clinical significance and expression of Bcl-2 protein in patients with systemic lupus erythematosus]

OBJECTIVE

To investigate the pathogenesis and clinical evaluation for expression of Bcl-2 in lymphocytes and renal tissues of 31 patients with systemic lupus erythematosus (SLE).

METHODS

Bcl-2 protein levels in T, B cells and renal tissues were examined by two-colour cytofluorography, and immunohistochemical staining (LSAB method) respectively.

RESULTS

Compared with inactive SLE patients and normal controls, a proposition of T cells (including CD(3)(+), CD(4)(+) and CD(8)(+) subgroups) expressing Bcl-2 protein increased significantly in active SLE patients. However, Bcl-2 protein levels are not statistically different in CD(19)(+) B cells among all groups. Mean fluorescence intensity (MFI) levels of Bcl-2 protein on CD(3)(+) T cells was positively related to SLE disease activity index (SLEDAI) among the SLE patients, which wasn't related to ESR, complement (C(3), C(4)) and autoantibody (ANA, anti-dsDNA, anti-Sm) positivity. The population of Bcl-2 positive intraglomerular cells was correlated significantly with the grade of mesangial cell increase and the number of proliferating cell nuclear antigen (PCNA) positive glomerular cells, and 24-hour urinary protein.

CONCLUSION

Overexpression of apoptosis-related Bcl-2 protein might play an important rule in the prolonged proliferation of mesangial cells and glomerular hypercellularity and in the active period of SLE patients, Bcl-2 expression levels of peripheral blood T lymphocytes might serve as an active index for SLE.

Pain pathways involved in fear conditioning measured with fear-potentiated startle: lesion studies

It is well established that the basolateral amygdala is critically involved in the association between an unconditioned stimulus (US), such as a foot shock, and a conditioned stimulus (CS), such as a light, during classic fear conditioning. However, little is known about how the US (pain) inputs are relayed to the basolateral amygdala. The present studies were designed to define potential US pathways to the amygdala using lesion methods. Electrolytic lesions before or after training were placed in caudal granular/dysgranular insular cortex (IC) alone or in conjunction with the posterior intralaminar nuclei of the thalamus (PoT/PIL), and the effects on fear conditioning were examined. Pretraining lesions of both IC and PoT/PIL, but not lesions of IC alone, blocked the acquisition of fear-potentiated startle. However, post-training combined lesions of IC and PoT/PIL did not prevent expression of conditioned fear. Given that previous studies have shown that lesions of PoT/PIL alone had no effect on acquisition of conditioned fear, these results suggest that two parallel cortical (insula-amygdala) and subcortical (PoT/PIL-amygdala) pathways are involved in relaying shock information to the basolateral amygdala during fear conditioning.

[Construction of adenovirus type 7(vaccine strain) vector and expression of beta-galactosidase gene]

Human adenovirus type 7 DNA was extracted from purified virus cultured in WI-38 cells. The essential fragment (68-100 mu) of Ad7 DNA was used for constructing a non-defective Ad7 vector termed as pAd7 delta E3. The vector was characterized by a deletion at the E3 region that contains a multicloning site for the insertion of foreign genes. A helper-independent adenovirus type 7-beta-galactosidase recombinant was established. The recombinant contains the beta-galactosidase gene flanked by CMV early promoter and SV40 poly A signal. The constructed recombinant virus showed efficient capacity in expressing the foreign gene, beta-galactosidase.

Reduced transplant arteriosclerosis in plasminogen-deficient mice

Recent gene targeting studies indicate that the plasminogen system is implicated in cell migration and matrix degradation during arterial neointima formation and atherosclerotic aneurysm formation. This study examined whether plasmin proteolysis is involved in accelerated posttransplant arteriosclerosis (graft arterial disease). Donor carotid arteries from wild-type B10.A2R mice were transplanted into either plasminogen wild-type (Plg+/+) or homozygous plasminogen-deficient (Plg-/-) recipient mice with a genetic background of 75% C57BL/6 and 25% 129. Within 15 d after allograft transplantation, leukocytes and macrophages infiltrated the graft intima in Plg+/+ and Plg-/- recipient mice to a similar extent. In Plg+/+ recipients, the elastic laminae in the transplant media exhibited breaks through which macrophages infiltrated before smooth muscle cell proliferation, whereas in Plg-/- recipients, macrophages failed to infiltrate the transplant media which remained structurally more intact. After 45 d of transplantation, a multilayered smooth muscle cell-rich transplant neointima developed in Plg+/+ hosts, in contrast to Plg-/- recipients, in which the transplants contained a smaller intima, predominantly consisting of leukocytes, macrophages, and thrombus. Media necrosis, fragmentation of the elastic laminae, and adventitial remodeling were more pronounced in Plg+/+ than in Plg-/- recipient mice. Expression of the plasminogen activators (PA), urokinase-type PA (u-PA) and tissue-type PA (t-PA), and expression of the matrix metalloproteinases (MMPs), MMP-3, MMP-9, MMP-12, and MMP-13, were significantly increased within 15 d of transplantation when cells actively migrate. These data indicate that plasmin proteolysis plays a major role in allograft arteriosclerosis by mediating elastin degradation, macrophage infiltration, media remodeling, medial smooth muscle cell migration, and formation of a neointima.

[Cloning and sequencing of adenovirus type 7 vaccine strain 76.5-87 mu fragment]

Adenovirus 7(Ad7) vaccine strain has been used more than 30 years in US army recruits for prevention of Ad7 infection and has been proven to be safe and effective. Recent years more attention has been paid to exploring the possibilities of using it for gene therapy or making recombinant vaccine. In order to construct adenovirus 7 vector, Ad 7 vaccine strain 76.5-87 mu fragment was cloned and sequenced. The fragment contains 3,557 bp which encodes 6 proteins of E3 region, namely 12.1 kD, 19.2 kD, 20.1 kD, 20.5 kD, 10.3 kD and partial of 15.2 kD. Nucleotide sequences of all these proteins show a high homology with the corresponding region of human adenovirus prototype strain Ad 7(Ad 7p) and Ad 7h(the homology of nucleotide sequence of the 6 proteins is more than 97.2%). The equivalent of ORF 16.1 kD in Ad7p and Ad7h was mutation due to a base pair deletion. The region corresponding to ORF 7.7 kD in Ad7p was missing in Ad7v due to a deletion. The results should be helpful to the construction of Ad7v vectors.

Regulation of CD44 gene expression by the proinflammatory cytokine interleukin-1beta in vascular smooth muscle cells

The CD44 gene codes for a family of alternatively spliced, multifunctional adhesion molecules that participate in extracellular matrix binding, lymphocyte activation, cell migration, and tumor metastasis. In a mouse model of transplant-associated arteriosclerosis, CD44 protein was induced in the neointima of allografted vessels and colocalized with a subset of proliferating vascular smooth muscle cells (SMC). To elucidate the molecular mechanisms regulating CD44 expression in this model, we investigated the regulation of CD44 gene expression by interleukin (IL)-1beta. Treatment of rat aortic SMC with IL-1beta resulted in a 5.3-fold increase in cell surface CD44 expression. Northern analysis showed that IL-1beta promoted a dose- and time-dependent induction of CD44 mRNA which reached 6.6-fold after 48 h, and nuclear run-on analysis showed that IL-1beta increased the rate of CD44 gene transcription within 8 h of stimulation. In transient reporter gene transfection experiments in rat aortic SMC, a 1.4-kilobase fragment of the mouse CD44 5'-flanking sequence mediated this response to IL-1beta. Regulation of CD44 gene expression by the proinflammatory cytokine IL-1beta may contribute to SMC phenotypic modulation in the pathogenesis of arteriosclerosis.

[The effects of the multiple structural layer of Ti-cast on bond of porcelain fused to titanium]

OBJECTIVE

To study the effects of the multiple structural layer of Ti-cast on the bond of porcelain fused to titanium.

METHODS

The interfacial state and bond strength of porcelain-titanium were observed by EPM analysis and a shear test.

RESULTS

The results showed cracks were observed in the interface of porcelain-titanium in R1 (the group of multiple structural layer of Ti-cast), but there were no cracks in the interface of porcelain-titanium in R2 (the group of removed multiple structural layer from Ti-cast) and R3 (the group of wrought titanium). The width of elemental diffusion layer of R1, R2 and R3 were 29.03 microns, 6.90 microns and 7.01 microns respectively. The shear bond srength of R1, R2 and R3 were 29.45 MPa, 52.75 MPa and 48.32 MPa respectively. There were significant difference in the width of elemental diffusion layer and shear bond strength between R1 and R2, R3 (P < 0.01).

CONCLUSION

This investigation indicates that the multiple structural layer of Ti-cast should be removed before firing of porcelain.

[Sequence analysis of Ad7 vaccine strain 87 mu-97.4 mu fragment]

Adenovirus 7 vaccine strain(Ad7v) possesses potentiality to be used as a vector for producing recombinant vaccine. In order to construct Ad7 vector, the nucleotide sequence of a 3698 bp fragment(87 to 97.4 mu) of the virus DNA was analysed. The fragment encodes three ORFs namely, one ORF of early region 4(E4), one ORF of early region 3 and one ORF of fiber protein. The predicted amino acids of three ORFs(ORF 8.1 kD, 42.8 kD and 10.3 kD) share 33%, 43% and 44% homology with Ad2 E4 corresponding regions (ORF 3, ORF 4 and ORF 6/7) respectively. A comparison of the nucleotide and amino acid sequences of those fiber ORF demonstrated a higher homology between Ad7v and prototype strains of Ad7v than those between Ad7v and Ad7h. The Ad7v E3 15.4 kD protein shares 86%, 88%, 90% and 98.5% amino acid homology with the equivalent region of ad7h E3 15.3 kD protein, Ad4 E3 region 15 kD protein, Ad3 E3 15.3 kD and Ad7p E3 15.3 kD protein protein respectively, but only 68% with Ad2 E3 14.7 kD protein.

A novel polymorphism at codon 333 of human immunodeficiency virus type 1 reverse transcriptase can facilitate dual resistance to zidovudine and L-2',3'-dideoxy-3'-thiacytidine

Recent clinical trials examining 3'-azido-3'-deoxythymidine (AZT, zidovudine, or Retrovir) combined with L-2', 3'-dideoxy-3'-thiacytidine (3TC or lamivudine) have shown that combination therapy with these nucleoside analogs affords significant virological and clinical benefits. The addition of 3TC to AZT delays AZT resistance in therapy-naive patients and can restore viral AZT susceptibility in patients who previously received AZT alone. In some AZT-experienced patients, the virological response to AZT-3TC therapy is not sustained and virus resistant to both drugs can be identified. To gain insight into the possible mechanism of dual resistance, we studied a recently described variant resistant to both AZT and 3TC and obtained by simultaneous passage of an AZT-resistant clinical isolate in cell culture with AZT and 3TC. Genetic mapping and site-directed mutagenesis experiments demonstrated that a polymorphism at codon 333 (Gly to Glu) of human immunodeficiency virus type 1 reverse transcriptase (RT) was critical in facilitating dual resistance in a complex background of AZT and 3TC resistance mutations. To assess the potential clinical relevance of RT codon 333 changes, we studied dually resistant viruses from patients taking AZT and 3TC. Genetic mapping of RT molecular clones derived from patients' plasma samples demonstrated that in some cases polymorphism at codon 333 was responsible for facilitating dual resistance.

[Experimental study on the effect of abstinence with herbal preparation qingjunyin]

The effect of herbal preparation Qingjunyin (QJY) on the animal model of drug dependence was studied. After the morphinistic models of white rats and mice were made by ever increasing doses of morphine each time, the animals were divided into large dosage QJY group, small dosage QJY group, sustained morphine group and control group. The withdrawal symptoms were observed after naloxone was given to the animals intraperitoneally. The results showed that QJY groups withdrawal symptoms of the addicted white rats were alleviated, the number of jumps of the addicted mice was reduced, the scores of the principal symptoms of the animals were decreased, while the body weights of the animals were gained, comparing with the control group, the difference was significant (P < 0.01). The effects of QJY enhanced in the large dosage group, which suggests QJY has abstinence effects.

[DNA cloning of Ad7 vaccine strain and sequence analysis of its Sma I H fragment]

Human adenoviruses have been a hot topic of study because of their potential utility for gene therapy and development of live viral vectored vaccines. Adenovirus types 4 and 7 have been given orally as vaccines for prevention of acute respiratory infections caused by these serotypes of adenovirus in U.S. army recruits for more than 30 years. Therefore, the advantage of using Ad4 and Ad7 as vectors in the development of oral live recombinant vaccine is obvious. For constructing Ad7 vector, 10.8-100 mu DNA of Ad7 vaccine strain has been cloned. The Sma I H fragment was sequenced using Ad7 DNA as a template and then the fragment was cloned by PCR. For verifying the sequence the fragment was sequenced again. The strategy we used to clone terminal end of adenovirus is reliable and practicable.

[Expression of hepatitis B virus S genes in Ad5 vector]

The hepatitis B virus (HBV) S gene, PreS2 + S genes and the late phase expression cassette (MTI) + HBV S genes were separately cloned into Ad5 vector downstream of E3 promoter (pAd5 deltaE3 provided by Wyeth Co.). The above constructed plasmids and Ad5 DNA EcoR I A fragment were cotransfected into 293 cells. The progeny adenoviruses named rAd5S, rAd5MS, rAd5S2S were harvested for analysis. The recombinants were isolated and analyzed by PCR, using two primers specific to the HBV S genes. The expressed products were detected by ELISA and RIA. The recombinant containing MIT + HBV S genes (rAd5MS) was identified to be ELISA positive, whereas the other two recombinants (rAd5S, rAd5S2S) were negative to ELISA, but positive to RIA. The results indicated that adenovirus E3 early promoter could express the inserted foreign genes, and MIT worked well in the E3 region of Ad5 and could increase the expression capacity of the recombinants. The conditions for foreign gene expression and genetic stability of the recombinant viruses were studied in detail. There was no wild Ad5 discovered during the cotransfection experiments. The present study provides some experiences for studying adenovirus recombination.