Effect of fuel aromatic content on PAH emission from a heavy-duty diesel engine

Polycyclic aromatic hydrocarbons (PAHs) emission tests for a heavy-duty diesel engine fueled with blend base diesel fuel by adding batch fractions of poly-aromatic and mono-aromatic hydrocarbons, Fluorene and Toluene, respectively, were simulated to five steady-state modes by a DC-current dynamometer with fully automatic control system. The main objective of this study is to investigate the effect of total aromatic content and poly-aromatic content in diesel fuels on PAH emission from the HDD engine exhaust under these steady-state modes. The results of this study revealed that adding 3% and 5% (fuel vol%) Fluorene in the diesel fuel increases the amount of total-PAH emission by 2.6 and 5.7 times, respectively and increases the amount of Fluorene emission by 52.9 and 152 times, respectively, than no additives. However, there was no significant variation of PAH emission by adding 10% (vol%) of Toluene. To regulate the content of poly-aromatic content in diesel fuel, in contrast to the total aromatic content, will be more suitable for the management of PAH emission.

Reoperative coronary artery bypass grafting without cardiopulmonary bypass

Conventional reoperative coronary artery bypass grafting (CABG) is associated with increased surgical risk. The use of less invasive methods to perform myocardial revascularization may, therefore, be more suitable, especially for high-risk patients. In June 1999, we performed three reoperative CABG surgeries, without the use of cardiopulmonary bypass, through unilateral or bilateral thoracotomy. One patient had single-vessel disease and the other two had multiple-vessel disease. All three patients had uneventful postoperative recovery. During early postoperative follow-up, all three patients were angina-free and were in New York Heart Association functional class I. The results of these three cases suggest that minimally invasive reoperative CABG may reduce morbidity compared with conventional reoperative CABG.

Structural features and regulatory properties of the brain glutamate decarboxylases

It is widely recognized that the two major forms of GAD present in adult vertebrate brains are each composed of two major sequence domains that differ in size and degree of similarity. The amino-terminal domain is smaller and shows little sequence identity between the two forms. This domain is thought to mediate the subcellular targeting of the two GADs. Substantial parts of the amino-terminal domain appear to be exposed and flexible, as shown by proteolysis experiments and the locations of posttranslational modifications. The carboxyl-terminal sequence domain contains the catalytic site and shows substantial sequence similarity between the forms. The interaction of GAD with its cofactor, pyridoxal-5' phosphate (pyridoxal-P), plays a key role in the regulation of GAD activity. Although GAD(65) and GAD(67) interact differently with pyridoxal-P, their cofactor-binding sites contain the same set of nine putative cofactor-binding residues and have the same basic structural fold. Thus the cofactor-binding differences cannot be attributed to fundamental structural differences between the GADs but must result from subtle modifications of the basic cofactor-binding fold. The presence of another conserved motif suggests that the carboxyl-terminal domain is composed of two functional domains: the cofactor-binding domain and a small domain that closes when the substrate binds. Finally, GAD is a dimeric enzyme and conserved features of GADs superfamily of pyridoxal-P proteins indicate the dimer-forming interactions are mediated mainly by the carboxyl-terminal domain.

Human skin Langerhans cells are targets of dengue virus infection

Dengue virus (DV), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine. Macrophages are important in dengue pathogenesis; however, the initial target cell for DV infection remains unknown. As DV is introduced into human skin by mosquitoes of the genus Aedes, we undertook experiments to determine whether human dendritic cells (DCs) were permissive for the growth of DV. Initial experiments demonstrated that blood-derived DCs were 10-fold more permissive for DV infection than were monocytes or macrophages. We confirmed this with human skin DCs (Langerhans cells and dermal/interstitial DCs). Using cadaveric human skin explants, we exposed skin DCs to DV ex vivo. Of the human leukocyte antigen DR-positive DCs that migrated from the skin, emigrants from both dermis and epidermis, 60-80% expressed DV antigens. These observations were supported by histologic findings from the skin rash of a human subject who received an attenuated tetravalent dengue vaccine. Immunohistochemistry of the skin showed CD1a-positive DCs double-labeled with an antibody against DV envelope glycoprotein. These data demonstrate that human skin DCs are permissive for DV infection, and provide a potential mechanism for the transmission of DV into human skin.

Identification of a novel point mutation (S65T) in alpha-galactosidase A gene in Chinese patients with Fabry disease. Mutations in brief no. 169. Online

Fabry disease is an X-linked inborn error of sphingolipid catabolism resulting from deficient enzyme activity of alpha-galactosidase A. The molecular defects of human alpha-galactosidase A gene causing Fabry disease have been characterized, including gene rearrangement and point mutations, which show the genetic heterogeneity in Fabry disease. To characterize the molecular defects of these patients, each exon of alpha-galactosidase A gene including intron-exon junctions were PCR amplified using biotin-labelled primer and sequenced using magnetic beads solid-phase sequencing. A G to C transversion was identified in the last nucleotide of exon 1 in two unrelated Chinese patients. This mutation obliterates an EcoN1 restriction site. Family studies show close linkage with the affected family members. Screening of 100 alleles (22 males, 39 females) of unrelated normal Chinese can not find this mutation. This mutation not only changes the amino acid from serine to threonine, but also likely cause splicing defects. To our knowledge, this is the first report of mutation in Chinese patients with Fabry disease, and a novel mutation causing Fabry disease not reported in literature previously.

Modified arterial switch operation by spiral reconstruction of the great arteries in transposition

BACKGROUND

Spiral relationship of the normally related great arteries (SRGA) has never been reconstructed in an arterial switch operation.

METHODS

From March 1998 to April 1999, 9 consecutive cases of transposition of the great arteries (TGA) family (from 2 days to 1.6 years old) underwent arterial switch operations with SRGA at our hospital. Two had a congenitally corrected TGA (plus atrial redirection). Lecompte maneuver was not used in all. The posterior wall of pulmonary trunk was not divided but three were reattached, two of whom had had previous pulmonary trunk banding. Thus the wall was shared between the great arteries facing each other.

RESULTS

All survived the operation. Supraaortic stenosis was balloon-dilated in 2 cases of early series, but technical modifications later were able to avoid it. Angiogram showed smooth flow into SRGA without upward and anterior tilting of the pulmonary bifurcation. All great and coronary arteries were patent. All were doing well on follow-up (16.5 +/- 4.2 months).

CONCLUSIONS

We concluded that the techniques to relocate the coronary arteries using common wall and in situ switch could also be applied to pulmonary arterial reconstruction, so that SRGA can be resumed in TGA.

Enhanced toxicity of Bacillus thuringiensis Cry3A delta-endotoxin in coleopterans by mutagenesis in a receptor binding loop

We used site-directed mutagenesis to modify the Bacillus thuringiensis cry3A gene in amino acid residues 350-354. Two mutant toxins, A1 (R(345)A,Y(350)F,Y(351)F) and A2 (R(345)A,DeltaY(350), DeltaY(351)), showed significantly improved toxicity against Tenebrio molitor (yellow mealworm). The mutant toxin A1 was also more potent against both Leptinotarsa decemlineata (Colorado potato beetle) and Chrysomela scripta (cottonwood leaf beetle), while A2 displayed enhanced toxicity only in L. decemlineata. Competitive binding assays of L. decemlineata brush border membrane vesicles (BBMV) revealed that binding affinities for the A1 and A2 mutant toxins were ca. 2.5-fold higher than for the wild-type Cry3 toxin. Similar binding assays with C. scripta BBMV revealed a ca. 5-fold lower dissociation rate for the A1 mutant as compared to that of Cry3A.

First successful ventricular septation of double inlet left ventricle in Taiwan

Patients with a double inlet ventricle may undergo surgery using a modified Fontan procedure, in which the pulmonary ventricle is not utilized, or a procedure in which a pulmonary ventricle is created through ventricular septation. Ventricular septation is preferred to the Fontan procedure because there is better cardiorespiratory response to exercise after surgery. A 4-year-old girl with Holmes heart underwent ventricular septation on 12 May 1998. Pulmonary artery banding had been performed at 3 months of age and rebanding 16 days later. She was well and continued to grow. Ultrafast computed tomography and cardiac catheterization prior to surgery showed a double inlet left ventricle (LV) connected to a right posterior aorta with a right-sided rudimentary right ventricle that drained to the left anterior pulmonary trunk. Left ventricular end diastolic volume was 218% of normal and the ejection fraction was 79%. After debanding and enlargement of the bulboventricular foramen, a 3 x 4-cm composite patch of equine pericardium and Dacron velour was used to septate the ventricle, with transmural stitching at the apical portion. The patient survived the operation with complete atrioventricular block, and was extubated 6 days later. A permanent pacemaker was implanted 1 month later. One year after surgery, she was doing well. Echocardiography revealed paradoxical septal motion with good ventricular function. This is the first report of successful ventricular septation of a double inlet left ventricle performed in Taiwan.

Concomitant management of airway and its adjacent vascular pathology in addition to repair of congenital cardiac defects

Respiratory symptoms are often present in infants with congenital cardiac anomalies, but the intrinsic pathology of the airway itself or external compression by abnormal vessels is frequently undetected before cardiac repair. We collected 12 patients with airway pathology from July 1996 to October 1998; all had definite diagnosis of lesions of the airway and its adjacent vessels by preoperative ultrafast computed tomography. Four had intrinsic pathology (one retrotracheal diverticulum, three tracheal stenosis) as well as external compression. Among them, six had complete vascular ring, four partial rings and three had bronchial compression by aneurysmal dilatation of branch pulmonary arteries. Simultaneous airway repair (one diverticulectomy, three patch tracheoplasty) and external decompression were performed in ten cases under cardiopulmonary bypass, nine of ten had simultaneous cardiac repair; the other two were done before cardiac repair. All survived except three. We concluded that ultrafast computed tomography is indispensable for definite diagnosis of airway and adjacent cardiovascular pathology. Mere repair of congenital cardiac defects without rectification of the airway and its adjacent structures is incompatible with survival.

Epitope randomization redefines the functional role of glutamic acid 110 in interleukin-5 receptor activation

Sequence randomization through functional phage display of single chain human interleukin (IL)-5 was used to investigate the limits of replaceability of the Glu(110) residues that form a part of the receptor-binding epitope. Mutational analysis revealed unexpected affinity for IL-5 receptor alpha chain with variants containing E110W or E110Y. Escherichia coli-expressed Glu(110) variants containing E110W in the otherwise sequence-intact N-terminal half, including a variant with an E110A replacement in the sequence-disabled C-terminal half, were shown by their CD spectra to be folded into secondary structures similar to that of single chain human IL-5 (scIL-5). Biosensor kinetics analysis revealed that (E110W/A5)scIL-5 and (E110W/A6)scIL-5 had receptor alpha chain binding affinities similar to that of (wt/A5)scIL-5. However, (E110W/A6)scIL-5 had a significantly reduced bioactivity in TF-1 cell proliferation compared with both (wt/A5)scIL-5 and (E110W/A5)scIL-5, and this activity reduction was disproportionately greater than the much smaller effect of Glu(110) mutation on receptor binding affinity. The marked and disproportionate decrease in TF-1 proliferation observed with (E110W/A6)scIL-5 suggests a role for Glu(110) in the biological activity mediated by the signal transducing receptor betac subunit of the IL-5 receptor. This is also consistent with the lack of stimulation of JAK2 phosphorylation by the (E110W/A6)scIL-5 mutant in recombinant 293T cells, as compared with the concentration-dependent stimulation seen for scIL-5. The results reveal the dispensability of charge in the Glu(110) locus of IL-5 for receptor alpha chain binding and, in contrast, its heretofore underappreciated importance for receptor activation.

Midterm results of aortic valve reconstruction for congenital aortic stenosis with or without regurgitation

Aortic valve is often replaced if valvular stenosis fails to be balloon dilated. Aortic valve reconstruction was performed on 4 patients from August 1993 to 1999. Their ages ranged from 1 month to 15 years (mean 8.3 years). Unicuspid aortic valve was present in three of them and bicuspid in the other one. Two patients were associated with a patent arterial duct, one aortic regurgitation, and one pulmonary stenosis. Commissurotomy was done in three of them to transform the aortic valve into tricuspid except one, in whom bicuspid valve was preserved. In one case with unicuspid aortic valve, a piece of tanned autologous pericardium was used to augment one myxomatous and retracted leaflet. The sinus of Valsalva was molded together with a bulging shape of its aortic leaflet. All four were weaned from cardiopulmonary bypass smoothly. Transesophageal echocardiography in one case prompted rebypass to decrease the degree of regurgitation from moderate to mild by further shaping of the leaflet and sinus of Valsalva. In one patient chylopericardium was complicated and subsided in 5 days after conservative treatment. All patients were doing well on follow up at 56.8 +/- 34.4 months after surgery, with trivial to mild systolic pressure gradient (20 +/- 26 mmHg; preoperatively: 88 +/- 36 mmHg) and mild regurgitation. Aortic valve reconstruction is feasible in the setting of congenital aortic stenosis in our limited experience; repair instead of replacement is recommended even when regurgitation is present.

Nodular tertiary syphilis mimicking granuloma annulare

We describe a 47-year-old man with annular plaques on the arms and torso that were treated as granuloma annulare, based on clinical and histopathologic findings. Exacerbation of the lesions during treatment with topical corticosteroids prompted a search for an infectious cause, which proved to be syphilis in the tertiary stage. The clinician should maintain a high index of suspicion for syphilis in the differential diagnosis of unusual annular skin lesions in a patient with noncaseating granulomas seen on skin biopsy.

Comparison of two rapid diagnostic assays for detection of immunoglobulin M antibodies to dengue virus

Two easy-to-use commercial diagnostic assays, a dipstick enzyme-linked immunosorbent assay (ELISA) (Integrated Diagnostics, Baltimore, Md.) and an immunochromatographic card assay (PanBio, Brisbane, Australia) were evaluated for detection of immunoglobulin M (IgM) antibody to dengue virus with an in-house IgM antibody capture microplate ELISA as a reference assay. The dipstick ELISA was based on the indirect-ELISA format using dengue 2 virus as the only antigen and enzyme-labeled goat anti-human IgM antibody as the detector. The total assay time was 75 min. The immunochromatographic card assay was based on the antibody capture format and separately measured both anti-dengue virus IgM and IgG in the same test. Colloidal-gold-labeled anti-dengue virus monoclonal antibody bound with dengue virus 1 to 4 antigen cocktail was the detector, and anti-human IgM and IgG were the capture antibodies. The total assay time was <10 min. Sera from 164 individuals classified as either anti-dengue virus IgM positive (94) or anti-dengue virus IgM negative (70) in the reference microplate ELISA with a dengue virus 1 to 4 antigen cocktail were tested in the two commercial assays. The dipstick ELISA missed 7 of 94 positive samples, for a sensitivity of 92.6%, while the immunochromatographic card assay missed two positive samples, for a sensitivity of 97.9%. Of the 70 negative samples, four were false positive by the dipstick ELISA and two were false positive in the immunochromatographic card assay, resulting in specificities of 94.3 and 97.1%, respectively. Both commercial assays provide sensitive and specific detection of anti-dengue virus IgM antibody and could prove useful in settings where the microplate ELISA is impractical.

Specific interaction of the 70-kDa heat shock cognate protein with the tetratricopeptide repeats

Using a yeast two-hybrid system with the 70-kDa heat shock cognate protein (hsc70) or its C-terminal 30-kDa domain as baits, we isolated several proteins interacting with hsc70, including Hip/p48 and p60/Hop. Both are known to interact with hsc70. Except for Hip/p48, all of the proteins that we isolated interact with the 30-kDa domain. Moreover, the EEVD motif at the C terminus of the 30-kDa domain appears essential for this interaction. Sequence analysis of these hsc70-interacting proteins reveals that they all contain tetratricopeptide repeats. Using deletion mutants of these proteins, we demonstrated either by two-hybrid or in vitro binding assays that the tetratricopeptide repeat domains in these proteins are necessary and sufficient for mediating the interaction with hsc70.

Transport of human growth hormone across Caco-2 cells with novel delivery agents: evidence for P-glycoprotein involvement

Emisphere Technologies, Inc. has synthesized a series of small molecules which have been shown to improve protein absorption through mucosal tissue. This enhancement is specific between protein and a particular delivery agent. Despite the specificity of interaction, the mechanism of enhanced tissue penetration is still unclear. The purpose of this work is to understand the enhancement mechanism(s) of these delivery agents by using Caco-2 cells as a model membrane. It was found that the bidirectional transepithelial fluxes of human growth hormone (hGH) in the presence of these delivery agents across human intestinal epithelial Caco-2 cell line showed marked asymmetry. Average permeability coefficient values obtained in the apical (AP) to basolateral (BL) direction were lower than those of the reverse (BL to AP) direction. On the other hand, the fluxes for human growth hormone alone were symmetric. When P-glycoprotein inhibitors were included in the transport medium, the permeability coefficient values of BL to AP direction were significantly decreased while the transport was increased in the reverse direction in the presence of delivery agents. P-glycoprotein inhibitors had no effect on the transport of human growth hormone alone. This study shows that human growth hormone alone can be transported across Caco-2 cells in very limited quantities by passive diffusion, but in the presence of delivery agents, human growth hormone can be effluxed in a P-glycoprotein-mediated fashion. This also indirectly shows that the human growth hormone has become more lipophilic in the presence of delivery agents.

A new sulfated beta-galactan from clams with anti-HIV activity

A new polysaccharide composed of galactan sulfate with a beta-(1-->3)-glycosidic linkage has been isolated from the marine clam species Meretrix petechialis. The polysaccharide was homogeneous in its composition containing D-galactose. The glycosidic linkage was examined by 2D DQF-COSY and 2D NOESY spectroscopy. The coupling constant of anomeric proton was 7.8 Hz, suggesting a beta-galacto configuration. The downfield shift of H-2 of galactose residue demonstrated the presence of 2-O-sulfonate group. TQF-COSY confirmed that the C-6 position was substituted with a sulfonate group. The anti-HIV activity of the polysaccharides has been evaluated by the inhibition of syncytia formation. The fusion index and percentage fusion inhibition of sulfated galactan were 0.34 and 56% at 200 micrograms/mL.

Transcellular and lipophilic complex-enhanced intestinal absorption of human growth hormone

PURPOSE

To evaluate the transcellular mechanism of novel enhancers absorption enhancement of human growth hormone (hGH), by examining the involvement of a P-glycoprotein-like efflux system, changes in membrane fluidity, and membrane damage.

METHODS

Caco-2 cell monolayers were grown on Snapwell filter supports and placed in a side-by-side diffusion apparatus. Transport in both the apical to basolateral (AP to BL) and basolateral to apical (BL to AP) direction was measured at different temperatures and in the presence of potential inhibitors. Fluorescence anisotropy measurement was used to measure membrane fluidity. The fluorescence anisotropy of DPH- and TMA-DPH-labeled cell suspensions was measured at room temperature. LDH (a measure of cytosolic lactate dehydrogenase) leakage assay was used to evaluate cytotoxicity.

RESULTS

The bi-directional transepithelial fluxes of hGH in the presence of these novel enhancers across Caco-2 cells showed marked asymmetry. Average permeability coefficient values obtained in the apical to basolateral (AP to BL) direction were lower than those of the reverse (BL to AP) direction. On the other hand, the fluxes for hGH alone were symmetric. When P-gp-like efflux inhibitors were included in the transport medium, the permeability coefficient value of BL to AP direction was significantly decreased while the transport was increased in the reverse direction in the presence of novel enhancers. In addition, lowering the temperature to 25 degrees C completely eliminated the asymmetry of hGH transport in the presence of novel enhancers. It was also shown by fluorescence anisotropy that these novel enhancers alone only slightly increased membrane fluidity. On the other hand, upon addition of hGH to the novel enhancers, the cell membrane showed a dramatic change as compared to treatment with novel enhancers alone. The results from the LDH assay showed that the novel enhancers and/or hGH did not cause cell damage, at least up to 1 hour, and the damage seen at the 2 hour point is also much lower than other known enhancers.

CONCLUSIONS

This study shows that human growth hormone alone cannot be transported across Caco-2 cells, except in small quantities, by passive diffusion, but in the presence of novel enhancers, human growth hormone permeation is substantial. In addition, the asymmetry of transport of the complexed hGH appears to be due to a P-gp-like efflux system. Assuming that the present substrate specificity of the P-gp-like efflux system shows the same preference for hydrophobic molecules as p-gp, the present work also indirectly shows that human growth hormone has become more lipophilic in the presence of these novel enhancers. Furthermore, membrane fluidity data also supports the premise that these novel enhancers interact and stabilize hGH, to make them more hydrophobic and easier to be transported through cell membranes.

Randomization of the receptor alpha chain recruitment epitope reveals a functional interleukin-5 with charge depletion in the CD loop

We report the functional phage display of single chain human interleukin-5 (scIL-5) and its use for receptor-binding epitope randomization. Enzyme-linked immunosorbent assays and optical biosensor analyses verified expression of scIL-5 on the phage surface and binding of scIL-5 phage to interleukin-5 receptor alpha chain. Furthermore, an asymmetrically disabled but functional scIL-5 mutant, (wt/A5)scIL-5, was displayed on phage. (wt/A5)scIL-5 was constructed from an N-terminal half containing the original five charged residues (88EERRR92) in the CD loop, including the Glu89 and Arg91 believed key in the alpha chain recognition site, combined with a C-terminal half containing a disabled CD loop sequence (88AAAAA92) missing the key recognition residues. This asymmetric variant was used as a starting point to generate an scIL-5 library in which the intact 88-92 N-terminal CD loop was randomized. From this epitope library, a receptor-binding variant of IL-5 was detected, (SLRGG/A5)scIL-5, in which the only charged residue in the CD loop is an Arg at position 90. Characterization of this variant expressed as a soluble protein in E. coli shows that the IL-5 pharmacophore for receptor alpha chain binding can function with a single positive charge in the CD loop. Charge-depleted CD loop mimetics of IL-5 suggest the importance of charge distribution in functional IL-5 receptor recruitment.

Enhancing in vivo tumorigenicity of B16 melanoma by overexpressing interferon regulatory factor-2: resistance to endogenous IFN-gamma

We investigated the role of interferon (IFN) regulatory factor-2 (IRF-2) as an oncoprotein in vivo, opposing endogenous IFN-gamma suppression of tumor growth. Using syngeneic IFN-gamma knockout mice, we show that endogenous IFN-gamma slows growth of the mouse melanoma cell line B16-F10 in immunocompetent mice, suggesting that tumor cell resistance to IFN-gamma may lead to greater tumorigenicity. IRF-2 is a nuclear transcription factor induced by IFN-gamma that represses numerous IFN-inducible genes, including genes that regulate cell growth, in opposition to the transcriptional activator IRF-1. B16-F10 has a marked growth inhibitory response to IFN-gamma in vitro and has very little IRF-2 induction compared with other murine tumor cell lines. We engineered B16-F10 cells to stably overexpress murine IRF-2. In vitro, these transfected cells showed a marked resistance to the growth-inhibitory effect of IFN-gamma. In normal mice the IRF-2-transfected cells grew much faster than control tumors. In syngeneic IFN-gamma knockout mice, control cells grew at a rate similar to that of IRF-2-transfected cells, implicating resistance to endogenous IFN-gamma as playing the major role in enhanced growth of IRF-2-transfected tumors in intact mice. These experiments demonstrate that (1) IRF-2 enhances B16 melanoma growth and increases resistance to IFN-gamma in vitro, and (2) IRF-2 opposes the growth suppression mediated by endogenous IFN-gamma in vivo.

One-stage repair of interrupted aortic arch and aortopulmonary window with an autologous arterial flap

Interrupted aortic arch associated with an aortopulmonary window is a rare congenital malformation that requires an early diagnosis and surgical treatment to avoid irreversible pulmonary vascular changes. We describe herein successful one-stage repair in a neonate without the use of pericardium or other prosthetic material. Use of a transaortic approach permitted both accurate planning of the appropriate size of pulmonary trunk flap and also facilitated easy repair of the aortopulmonary septal defect. The growth potential of both great arteries was optimized.

Purification and characterization of a serine protease with fibrinolytic activity from Tenodera sinensis (praying mantis)

Mantis egg fibrolase (MEF) was purified from the egg cases of Tenodera sinensis using ammonium sulfate fractionation, gel filtration on Bio-Gel P-60 and affinity chromatography on DEAE Affi-Gel blue gel. The protease was assessed homogeneous by SDS-polyacrylamide gel electrophoresis and has a molecular mass of 31500 Da. An isoelectric point of 6.1 was determined by isoelectric focusing. Amino acid sequencing of the N-terminal region established a primary structure composed of Ala-Asp-Val-Val-Gln-Gly-Asp-Ala-Pro-Ser. MEF readily digested the Aalpha- and Bbeta-chains of fibrinogen and more slowly the gamma-chain. The nonspecific action of the enzyme results in extensive hydrolysis of fibrinogen and fibrin releasing a variety of fibrinopeptide. The enzyme is inactivated by Cu2+ and Zn2+ and inhibited by PMSF and chymostatin, yet elastinal, aprotinin, TLCK, TPCK, EDTA, EGTA, cysteine, beta-mercaptoethanol, iodoacetate, E64, benzamidine and soybean trypsin inhibitor do not affect activity. Antiplasmin was not sensitive to MEF but antithrombin III inhibited the enzymatic activity of MEF. Among chromogenic protease substrates, the most sensitive to MEF hydrolysis was benzoyl-Phe-Val-Arg-p-nitroanilide with maximal activity at pH 7.0 and 30 degrees C. MEF preferentially cleaved the oxidized B-chain of insulin between Leu15 and Tyr16. D-Dimer concentrations increased on incubation of cross-linked fibrin with MEF, indicating the enzyme has a strong fibrinolytic activity.

Early metabolic inhibition-induced intracellular sodium and calcium increase in rat cerebellar granule cells

1. Possible mechanisms responsible for the increases in intracellular calcium ([Ca2+]i) and sodium ([Na+]i) levels seen during metabolic inhibition were investigated by continuous [Ca2+]i and [Na+]i measurement in cultured rat cerebellar granule cells. An initial small mitochondrial Ca2+ release was seen, followed by a large influx of extracellular Ca2+. A large influx of extracellular Na+ was also seen. 2. The large [Ca2+]i increase was not due to opening of voltage-dependent or voltage-independent calcium channels, activation of NMDA/non-NMDA channels, activation of the Na+i-Ca2+o exchanger, or inability of plasmalemmal Ca2+-ATPase to extrude, or mitochondria to take up, calcium. 3. The large [Na+]i increase was not due to activation of the TTX-sensitive Na+ channel, the Na+i-Ca2+o exchanger, the Na+-H+ exchanger, or the Na+-K+-2Cl- cotransporter, or an inability of Na+-K+-ATPase to extrude the intracellular sodium. 4. Phospholipase A2 (PLA2) activation may be involved in the large influx, since both were completely inhibited by PLA2 inhibitors. Moreover, melittin (a PLA2 activator) or lysophosphatidylcholine or arachidonic acid (both PLA2 activation products) caused similar responses. Inhibition of PLA2 activity may help prevent the influx of these ions that may result in serious brain injury and oedema during hypoxia/ischaemia.

An in vitro study of the effects of Doppler angle, fibrinogen, and hematocrit on ultrasonic Doppler power

For a better understanding of the relationship between the Doppler power and erythrocyte aggregation of whole blood under steady flow in a conduit, the effects of Doppler angle, fibrinogen concentration, and hematocrit were investigated in a mock flow loop. The results show that, at a mean shear rate of 102 s(-1), there was minimal angular dependence; but at a mean shear rate of 52 s(-1), there was a weak angular dependence as the Doppler angle was varied from 40 degrees to 70 degrees . These results suggest that there was, perhaps, no or little alignment of the red cell aggregates at high shear rates. The Doppler power was found to increase nonlinearly as the fibrinogen concentration was increased; and the effect of other plasma proteins on red cell aggregation may not be negligible, although fibrinogen is the dominant factor. The results show that the variation of the Doppler power over the lumen is hematocrit dependent for hematocrits below 26%

Binding of heptapeptides or unfolded proteins to the chimeric C-terminal domains of 70-kDa heat shock cognate protein

Seventy-kDa heat shock cognate protein (hsc70) and its homologs in bacteria, yeast and vertebrates are known to form complexes with S-carboxymethyl-alpha-lactalbumin (CMLA), an unfolded protein; and, this activity has been attributed to its C-terminal 30-kDa domain. Herein, we show that hsc70s isolated from the seeds of mung bean and peas, however, are not effective in complexing with CMLA, and that the 30-kDa domain of Arabidopsis hsc70 (At30) cannot form stable complexes with CMLA either. Moreover, chimeric 30-kDa domains, either composed of rat 18-kDa and Arabidopsis 10-kDa subdomains (R18At10) or with Arabidopsis 18-kDa and rat 10-kDa subdomains (At18R10), were prepared and tested for their ability to complex with CMLA or a heptapeptide FYQLALT. At18R10 cannot complex with both CMLA and FYQLALT. On the other hand, R18At10 is capable of forming complexes with FYQLALT at a level similar to that of the rat 30-kDa domain (R30). R18At10 also forms complexes with CMLA, but the amount of the R18At10/CMLA complexes is much less than that of R30/CMLA. The results imply that the 18-kDa subdomain dictates the binding specificity for heptapeptide, and that the C-terminal 10-kDa subdomain may also provide some selection or restriction for unfolded proteins to form complexes with hsc70.

Chemical sulfonation and anticoagulant activity of acharan sulfate

Acharan sulfate is a glycosaminoglycan prepared from the giant African snail, Achatina fulica. This polysaccharide has a repeating disaccharide structure of -->4)-2-deoxy-2-acetamido-alpha-D-glucopyranose (1-->4)-2-sulfo-alpha-L-idopyranosyluronic acid (1-->). Its structure is related to heparin and heparan sulfate but is distinctly different from all known members of these classes of glycosaminoglycans. Because of its structural similarities to heparin, chemically modified acharan sulfate was studied to understand the chemical structure effected its anticoagulant activity. After de-N-acetylation, acharan sulfate was N-sulfonated using either chlorosulfonic acid-pyridine or sulfur trioxide-trimethylamine complex. The sulfate level in these products ranged from 22 to 24%(w/w), significantly less than that of heparin at 36%. The molecular weight of both N-sulfoacharan sulfates were comparable with that of heparin. In vitro anticoagulant activity assays showed that N-sulfoacharan sulfate derivatives were moderately active for the inhibition of thrombin and neither product showed any measurable anti-factor Xa activity. The differences in the activities of N-sulfoacharan sulfates produced by these two methods are probably ascribable to a small level of concomitant O-sulfonation obtained when using chlorosulfonic acid-pyridine.

In situ measurements of Doppler power vs. flow turbulence intensity in red cell suspensions

Whereas previous studies have shown that ultrasonic backscatter and Doppler power from blood are affected by flow turbulence, turbulence level has only been inferred from the flow Reynolds number and not directly measured. In this study, both ultrasonic Doppler power and flow turbulence intensity were measured in situ to quantify the relationship between Doppler power and flow turbulence. Three grid meshes of different geometries were used in a steady-flow mock loop to generate controlled levels of flow turbulence in porcine red blood cell saline suspensions. Doppler power was measured by a 10-MHz PW Doppler flowmeter, and the turbulence intensity by using constant-temperature hot film anemometry. We showed that Doppler power is affected by turbulence and hematocrit in a complex way. At a fixed hematocrit, Doppler power increases nonlinearly with turbulence intensity and, at fixed turbulence intensity, Doppler power peaks at an optimal hematocrit level that increases with turbulence level. The shape factor, introduced by Lucas and Twersky (1987) to take into account effects of shape and orientation of the scatterers in a dense distribution of small and tenuous scatterers, was estimated by fitting the experimental data to the theoretical model. The results indicate that shape factor decreases with increasing turbulence intensity.

Determination of the structure of oligosaccharides prepared from acharan sulfate

The fine structure of acharan sulfate, a recently discovered glycosaminoglycan isolated from Achatina fulica , was examined. This glycosaminoglycan has a major disaccharide repeating unit of -->4)-alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp2S(1--> (where GlcNpAc is N -acetylglucosamine, IdoAp is iduronic acid, and S is sulfate) making it structurally related to both heparin and heparan sulfate. Using heparin lyases prepared from Flavobacterium heparinum and a newly isolated heparinase from Bacteroides stercoris , the controlled enzymatic depolymerization of acharan sulfate was undertaken to prepare a mixture of oligosaccharides. Fractionation of this mixture of oligosaccharides by strong-anion-exchange high performance liquid chromatography afforded oligosaccharides that capillary electrophoresis established were sufficiently pure for structural characterization. Electrospray ionization mass spectrometry identified two series of oligosaccharides, one derived from acharan sulfate's major repeating unit and a second minor group of undersulfated oligosaccharides. Proton nuclear magnetic resonance spectroscopy established the structure of these two classes of oligosaccharides to be DeltaUAp2S(1-->[4)-alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp2S (1-->]n4)- D-GlcNpAcalpha,beta (where n = 0,1,2,3 and DeltaUAp is 4-deoxy-alpha-L- threo -hex-4-enopyranosyluronic acid) and DeltaUAp(1-->[4)- alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp2S(1-->]m-D-GlcNpAcal pha,beta (where m = 1,2,3). These results suggest the presence of minor sequence variants in acharan sulfate containing unsulfated iduronic acid having the structure -->4)-alpha-D-GlcNpAc(1-->4)-alpha-L-IdoAp(1-->.

Antiplatelet and antithrombotic effects of a combination of ticlopidine and ginkgo biloba ext (EGb 761)

The antiplatelet and antithrombotic effects of the oral combination treatment of ticlopidine and Ginkgo biloba extract (EGb 761) were studied in normal and thrombosis-induced rats. The ex vivo inhibitory effect on ADP-induced platelet aggregation of a small dose of ticlopidine (50 mg/kg/day) in combination with EGb 761 (40 mg/kg/day) was comparable to a larger dose of only ticlopidine (200 mg/kg/day). Bleeding time was also prolonged by 150%. Thrombus weight was also consistently decreased by a combination of ticlopidine and EGb 761 in an arterio-venous shunt model at two doses of ticlopidine (50 mg/kg) plus EGb 761 (20 mg/kg) and ticlopidine (50 mg/kg) plus EGb 761 (40 mg/kg). A combinatory treatment in acute thrombosis model in mice also showed a higher recovery than a single treatment.

Protective efficacy of a dengue 2 DNA vaccine in mice and the effect of CpG immuno-stimulatory motifs on antibody responses

A recently described DNA vaccine for dengue (DEN) type 2 was shown to elicit high levels of neutralizing antibodies in mice. The vaccine candidate consists of the PreM and 92% of the envelope genes of DEN 2 New Guinea C strain. We further evaluated this DNA vaccine candidate by examining the effect of immuno-stimulatory CpG DNA motifs on antibody response and by studying the protective efficacy of the vaccine. The results showed that CpG motifs present in pUC 19 significantly improved the antibody response to a suboptimal dose of 3.1 micrograms of the DEN DNA vaccine. In a lethal mouse intracerebral challenge model, the vaccine provided a significant level of protection. Sixty percent of the mice immunized with the DEN DNA vaccine plus pUC 19 survived the challenge compared to only 10% in the control group that received vector plus pUC. These studies illustrate that nucleic acid immunization is a viable approach to developing a DEN vaccine and that immuno-stimulatory CpG DNA motifs can be used to lower the minimum dose required to produce an antibody response.

Evaluation of the protective efficacy of a recombinant dengue envelope B domain fusion protein against dengue 2 virus infection in mice

A recombinant protein containing part of the dengue (DEN) 2 envelope protein was evaluated as a subunit immunogen for vaccination against DEN virus infection. A gene fragment encoding amino acids 298-400 (B domain) of the DEN-2 virus envelope was expressed as a fusion protein with the maltose binding protein (MBP) of Escherichia coli. This recombinant, DEN-2(B)/MBP, was purified and analyzed for its antigenicity, immunogenicity, and ability to protect mice against lethal challenge. The recombinant antigen reacted with a DEN-2 type-specific neutralizing monoclonal antibody (3H5), DEN-2 hyperimmune mouse ascitic fluid, and DEN-2 immune human sera. When administered to mice, DEN-2(B)/MBP elicited a DEN-2 virus neutralizing antibody response that conferred partial protection against challenge infection with a lethal dose of DEN-2 virus administered by intracranial inoculation. In addition, no replication of DEN-2 virus was detectable in the brains of the immunized mice as compared with control mice that were killed six days after challenge. Sera from immunized mice revealed no cross-neutralizing antibody to any of the other DEN serotypes in the plaque-reduction neutralization test. These findings warrant further studies with the DEN-2(B)/MBP antigen as a potential human vaccine candidate. An effective vaccine could prevent thousands of cases of illness and many deaths each year resulting from DEN virus infections.

Mutation analysis of the 6-pyruvoyl-tetrahydropterin synthase gene in Chinese hyperphenylalaninemia caused by tetrahydrobiopterin synthesis deficiency

Hyperphenylalaninemia (HPA) may be caused by deficiency of phenylalanine hydroxylase or tetrahydrobiopterin (BH4), the essential cofactor for the aromatic amino acid hydroxylases. 6-Pyruvoyl-tetrahydropterin synthase (PTPS) deficiency is a major cause of BH4 deficient HPA. In this study, seven single base mutations at nucleotides 73 (C>G), 155 (A>G), 166 (G>A), 209 (T>A), 259 (C>T), 286 (G>A), and 317 (C>T) on PTPS cDNA were detected in Chinese PTPS-deficient HPA by polymerase chain reaction and solid phase DNA sequencing. These nucleotide alterations result in R25G, N52S, V56M, V70D, P87S, D96N, and T106M amino acid substitutions, respectively. The R25G, V56M, V70D, and T106M were novel mutations found in PTPS gene. By analysis of 38 PTPS mutant alleles from 19 unrelated Chinese PTPS-deficient HPA families, the allele frequency of these mutations in Chinese PTPS-deficient HPA were determined to be approximately 5.3% (R25G), 34.2% (N52S), 7.9% (V56M), 2.6% (V70D), 36.8% (P87S), 7.9% (D96N), and 2.6% (T106M), respectively. Two common mutations, N52S and P87S, were found to account for 71% of the Chinese PTPS mutant alleles. The N52S mutation accounts for 48% of the southern Chinese PTPS mutation, but only one (9%) of the northern Chinese PTPS mutant allele was found to be N52S, which suggested that the N52S mutation might be southern Chinese. Clinically, the V56M mutation was found to associate with the mild form of PTPS deficiency. However, the R25G, N52S, P87S, and D96N were found mainly in the patients with severe clinical symptom. Using polymerase chain reaction-based mutation analysis, a fetus at risk of PTPS deficiency was diagnosed prenatally to be a carrier of N52S mutation.

Structural characteristics of brain glutamate decarboxylase in relation to its interaction and activation

The conformation, stability, cofactor interactions, and activation of a recombinant 65-kDa form of rat brain glutamate decarboxylase (GAD65) were investigated by using UV/visible spectrophotometry, fluorescence spectroscopy, circular dichroism, and differential scanning microcalorimetry. The enzyme was prepared from Sf9 insect cells infected with a recombinant baculovirus containing the entire GAD65 coding region. The UV/visible absorption spectrum of purified holoenzyme (holoGAD) exhibits two peaks in the range of 300-450 nm, which are due to the formation of a Schiff base when pyridoxal phosphate (pyridoxal-P) binds to GAD. Fluorescence emission intensity (excited at 295 or 280 nm) was substantially enhanced when pyridoxal-P was removed from holoGAD and quenched when pyridoxal-P was added to the apoenzyme (apoGAD). These observations implied that a significant enzyme conformational change occurs during the formation of holoGAD. Circular dichroism provided additional evidence for a conformational change, as the ellipticity of both negative (202-242 nm) and positive (188-202 nm) bands decreased when pyridoxal-P was removed from holoGAD. Secondary structure determination estimated that holoGAD contains a higher content of alpha-helix (34% versus 24%) and a lower content of beta-sheet (18% versus 30%) than apo-GAD. Differential scanning microcalorimetry indicated that holoGAD exhibits a much larger enthalpy and a 3 degrees C higher temperature of thermal unfolding than apoGAD, suggesting that holoGAD has a much tighter conformation and greater stability than apoGAD. A model describing the interaction of pyridoxal-P with GAD is presented, which proposes that an intermediate complex involving ionic interaction between the phosphate group of pyridoxal-P and the positive, charged residues in the active site of GAD maintains the pyridoxal-P molecule in an appropriate position in the active center. Simultaneously, this complex formation is accompanied by a moderate enzyme conformational change, providing a favorable configuration that enables the epsilon-amino of the active-site lysine to react with the aldehyde group of pyridoxal-P. The formation of active holoGAD involves a large enzyme conformational change, which leads to increased stability.

Evaluation of a dipstick enzyme-linked immunosorbent assay for detection of antibodies to dengue virus

Accurate serological confirmation of dengue (DEN) infection is difficult, because simple reliable assays for the detection of DEN antibodies are not available. To address this problem, a dipstick enzyme-linked immunosorbent assay (ELISA) was evaluated. The dipstick contained dots of serially diluted DEN 2 antigen. To detect immunoglobulin G (IgG), the dipstick was processed through four reaction cuvettes containing test serum, enhancer, enzyme-conjugated anti-human IgG and IgM antibody, and substrate. Total assay time was 45 min. To detect IgM, the serum was passed through a protein G device to remove IgG. The dipstick was then processed as before, except that the incubation times were longer and enzyme-conjugated anti-human IgM was used. The total assay time was 3 h. The dipstick ELISA results were compared with results from microplate ELISA. The IgG dipstick ELISA showed a sensitivity of 95.2% and a specificity of 100% compared to an IgG microplate ELISA with serum samples from 125 individuals living in an area in which DEN is endemic. In tests with 75 serum samples from patients with clinically suspected acute DEN infections, the IgM dipstick ELISA showed a sensitivity of 97.9% and specificity of 100% compared to those of an IgM antibody capture microplate ELISA. These results showed that the dipstick ELISA was a sensitive and specific test for the detection of either DEN IgM or IgG in human serum. The dipstick ELISA was also shown to be useful for detecting seroconversions to DEN IgM or IgG in paired serum samples from 20 patients with virus isolation-confirmed acute DEN infections.

Inoculation of plasmids expressing the dengue-2 envelope gene elicit neutralizing antibodies in mice

To develop a nucleic acid vaccine against dengue type-2 virus, the PreM and 92% of the envelope (E) genes were cloned into different eukaryotic plasmid expression vectors (pkCMVint Polyli and pVR1012). The resultant plasmid constructs (pD2ME and P1012D2ME) properly expressed the truncated E protein in vitro as evidenced by the expected protein size on SDS-PAGE and the ability of the protein to be recognized by monoclonal antibodies directed against conformational epitopes. Three-week-old BALB/c mice were given intradermal inoculations of each construct. Plasmid expression vectors without dengue genes were used as controls. One hundred percent of the mice that received the pD2ME and p1012D2ME constructs developed anti-dengue antibodies. These antibodies were shown to neutralize dengue type-2 virus in vitro. This is the first demonstration of the use of nucleic acid inoculation in the development of potential dengue virus. vaccines.

Melanoma in children and adolescents

Melanoma is a life-threatening and rare malignancy in childhood and adolescence. Because it is so uncommon, melanoma may not be recognized readily or considered seriously in a differential diagnosis, resulting in delays in definitive treatment. We review melanoma occurring in 13 patients under 20 years of age who presented to a single tertiary care children's hospital. Five patients had nonmetastatic primary cutaneous melanoma, with Breslow thickness measurement ranging from 0.84 to 7.8 mm. Three patients had metastatic primary cutaneous melanoma, three had metastatic melanoma arising ina congenital giant nevus, and two had primary leptomeningeal melanoma. All of the patients were given definitive surgical treatment; some received adjunctive radiation therapy and chemotherapy. Overall 5-year survival rate was 40.0% for all cutaneous melanomas, which included 100% for clinical stage I disease, and 0% for clinical stage II and III disease. Both patients with primary leptomeningeal melanoma died an average of 6 months following diagnosis. Nonmetastatic primary cutaneous melanoma is a survivable disease if detected early and treated by surgical excision; metastatic and leptomeningeal disease were uniformly fatal. Types of melanoma, risk factors for melanoma, and the role of the dermatologist in primary prevention and detection are discussed.

Genomic analysis of Epstein-Barr virus in nasal and peripheral T-cell lymphoma: a comparison with nasopharyngeal carcinoma in an endemic area

The Epstein-Barr virus (EBV) is prevalent in nasal and peripheral T-cell lymphoma (NPTL) in Taiwan, where nasopharyngeal carcinoma (NPC) is endemic. In order to understand the pathogenesis of these two malignancies in this endemic area, genomic analysis of EBV in NPTL with comparison to NPC is important. We investigated the EBV subtype (types A and B), BamH-I "f" variant, and the Xho-I site mutant of the latent membrane protein-1 (LMP-1) gene in 19 cases of EBV-associated NPTL and in 30 cases of NPC. EBV DNA from three patients with infectious mononucleosis (IM) was simultaneously studied as representative of normal healthy carriers. Similar to NPC and IM, the EBV in NPTL was found to belong to the type A strain in the majority (18 of 19) of cases by analyzing the 3' divergence of EBNA-2 genes. The extra restriction enzyme site in the BamHI-F region ("f" variant) of EBV DNA was frequently (15 of 30) demonstrated in NPC, but only rarely (1 of 19) was it detected in NPTL and IM (0 of 3). The Xho-I site mutant of the LMP-1 gene previously characterized in Chinese NPC also prevailed in NPTL and IM with an identical nucleotide sequence. No correlation exists between the EBV subtype and its variants. In conclusion, type A EBV is prevalent in Taiwanese NPTL, a finding much distinct from the dominance of type B virus in nonendemic European patients. The EBV genomes in NPTL are closely similar to those in IM or normal healthy carriers, but are distinct from NPC for the infrequency of the "f" variant. The prevalence of the LMP-1 mutant in this endemic region suggests that this EBV strain may confer a growth advantage role in the pathogenesis of these EBV-associated diseases. The rarity of the "f" variant in NPTL and its high frequency in NPC may explain the differential tumorigenesis of different EBV strains.

IFN regulatory factor-1 gene transfer into an aggressive, nonimmunogenic sarcoma suppresses the malignant phenotype and enhances immunogenicity in syngeneic mice

IFN-gamma has a direct antitumor effect on many tumor cell lines mediated through the IFN-gammaR. One effect of IFN-gamma is to induce the nuclear transcription factor IFN regulatory factor-1 (IRF-1), which may function as a tumor suppressor. In this study, mouse IRF-1 cDNA under a high constitutive expression promoter was transfected into the highly aggressive, nonimmunogenic MCA 101 murine sarcoma. Clones were obtained by G418 selection and screened for IRF-1 mRNA expression by reverse transcriptase-PCR (RT-PCR). High expression clones had high levels of two MHC class I proteins (H-2Kb and H-2Db) on the cell surface that correlated with increased levels of class I mRNA by RT-PCR. Furthermore, these clones also had increased levels of MHC class II protein (I-Ab), which correlated with increased levels of one subunit of class II mRNA by RT-PCR. IRF-1-expressing clones had markedly diminished cell growth in vitro and decreased anchorage-independent growth in a soft agar assay. These clones also demonstrated markedly prolonged tumor latency and slowed growth in syngeneic C57BL/6 mice. IRF-1 gene-transfected cells had shortened tumor latency and formed faster growing tumors in gamma-irradiated immunodeficient mice compared with results in immunocompetent mice. Mice immunized with IRF-1-transfected cells were protected against subsequent challenge with IRF-1 transfected cells and also demonstrated greater tumor latency and slower tumor growth against subsequent challenge with untransfected cells compared with mice immunized with empty vector-transfected cells. These studies demonstrate a tumor suppressor effect of IRF-1, which acts in vivo through both partial reversion of the malignant phenotype and enhanced immune recognition and may play a role in the antitumor effects of IFN-gamma.

IFN regulatory factor-1 gene transfer into an aggressive, nonimmunogenic sarcoma suppresses the malignant phenotype and enhances immunogenicity in syngeneic mice

IFN-gamma has a direct antitumor effect on many tumor cell lines mediated through the IFN-gammaR. One effect of IFN-gamma is to induce the nuclear transcription factor IFN regulatory factor-1 (IRF-1), which may function as a tumor suppressor. In this study, mouse IRF-1 cDNA under a high constitutive expression promoter was transfected into the highly aggressive, nonimmunogenic MCA 101 murine sarcoma. Clones were obtained by G418 selection and screened for IRF-1 mRNA expression by reverse transcriptase-PCR (RT-PCR). High expression clones had high levels of two MHC class I proteins (H-2Kb and H-2Db) on the cell surface that correlated with increased levels of class I mRNA by RT-PCR. Furthermore, these clones also had increased levels of MHC class II protein (I-Ab), which correlated with increased levels of one subunit of class II mRNA by RT-PCR. IRF-1-expressing clones had markedly diminished cell growth in vitro and decreased anchorage-independent growth in a soft agar assay. These clones also demonstrated markedly prolonged tumor latency and slowed growth in syngeneic C57BL/6 mice. IRF-1 gene-transfected cells had shortened tumor latency and formed faster growing tumors in gamma-irradiated immunodeficient mice compared with results in immunocompetent mice. Mice immunized with IRF-1-transfected cells were protected against subsequent challenge with IRF-1 transfected cells and also demonstrated greater tumor latency and slower tumor growth against subsequent challenge with untransfected cells compared with mice immunized with empty vector-transfected cells. These studies demonstrate a tumor suppressor effect of IRF-1, which acts in vivo through both partial reversion of the malignant phenotype and enhanced immune recognition and may play a role in the antitumor effects of IFN-gamma.

Emergency use of extracorporeal membrane oxygenation in a patient with post-cardiotomy myocardial stunning

Myocardial stunning refers to reversible postischemic myocardial dysfunction persisting after reperfusion. We report a patient who presented with biventricular failure, but exhibited neither definite electrocardiographic change nor elevation of serum cardiac enzyme levels in the post-cardiotomy period. The presentation was indicative of myocardial stunning. The patient's hemodynamics could not be maintained even with infusion of high doses of catecholamines. Extracorporeal membrane oxygenation successfully restored myocardial function. In conclusion, when the hemodynamic status of a patient with myocardial stunning cannot be maintained with inotropic agents, extracorporeal membrane oxygenation should be considered.

Genomic analysis of Epstein-Barr virus in nasal and peripheral T-cell lymphoma: a comparison with nasopharyngeal carcinoma in an endemic area

The Epstein-Barr virus (EBV) is prevalent in nasal and peripheral T-cell lymphoma (NPTL) in Taiwan, where nasopharyngeal carcinoma (NPC) is endemic. In order to understand the pathogenesis of these two malignancies in this endemic area, genomic analysis of EBV in NPTL with comparison to NPC is important. We investigated the EBV subtype (types A and B), BamH-I "f" variant, and the Xho-I site mutant of the latent membrane protein-1 (LMP-1) gene in 19 cases of EBV-associated NPTL and in 30 cases of NPC. EBV DNA from three patients with infectious mononucleosis (IM) was simultaneously studied as representative of normal healthy carriers. Similar to NPC and IM, the EBV in NPTL was found to belong to the type A strain in the majority (18 of 19) of cases by analyzing the 3' divergence of EBNA-2 genes. The extra restriction enzyme site in the BamHI-F region ("f" variant) of EBV DNA was frequently (15 of 30) demonstrated in NPC, but only rarely (1 of 19) was it detected in NPTL and IM (0 of 3). The Xho-I site mutant of the LMP-1 gene previously characterized in Chinese NPC also prevailed in NPTL and IM with an identical nucleotide sequence. No correlation exists between the EBV subtype and its variants. In conclusion, type A EBV is prevalent in Taiwanese NPTL, a finding much distinct from the dominance of type B virus in nonendemic European patients. The EBV genomes in NPTL are closely similar to those in IM or normal healthy carriers, but are distinct from NPC for the infrequency of the "f" variant. The prevalence of the LMP-1 mutant in this endemic region suggests that this EBV strain may confer a growth advantage role in the pathogenesis of these EBV-associated diseases. The rarity of the "f" variant in NPTL and its high frequency in NPC may explain the differential tumorigenesis of different EBV strains.

Probing the mechanism of action of Bacillus thuringiensis insecticidal proteins by site-directed mutagenesis--a minireview

The current model of the mechanism of action of several Bacillus thuringiensis insecticidal crystal proteins (Cry) is reviewed and tested by site-directed mutagenesis experiments. Amino acid (aa) residues were substituted in each of the three domains of Cry toxins and the effects on toxin stability, binding to receptors, irreversible insertion into the membrane, and ion channel activity were examined. Mutant proteins with aa altered on the putative membrane-proximal surface of domain I are affected in insertion into the membrane and toxicity, but not in binding to the receptor. Alterations in the putative receptor-binding loops of domain II show an effect on the initial (reversible) binding to the receptor when certain aa are altered, while affecting irreversible binding when other aa are altered. Mutant proteins with aa altered in a conserved track of aa of domain III have altered ion channel properties, as measured by the voltage clamping of insect midguts and the K+ permeability of brush border membrane vesicles. In summary, domain I is involved in insertion into the membrane and affects ion channel function, domain II is involved in receptor binding and insertion into the membrane, and domain III is involved ion channel function, receptor binding, and insertion into the membrane.

Optical and digital techniques for enhancing radiographic anatomy for identification of human remains

Out of a total of more than 300 radiographic identifications made by one of us (JJF), there were 11 cases in which radiologic adjuncts were used because the antemortem radiographs were either miniaturized or because anatomical landmarks could not be clearly discerned. The techniques used included slide projection (two cases), photographic enlargement and enhancement (two cases), digitization (three cases), and digitization with computer enhancement (three cases), commercial digitization (one case). In a 12th case, where identification was made by comparison of antemortem and postmortem film X-rays, the films were digitized as a further evaluation of a commercial system. This is the first reported use of these techniques.

The epidemiology of dengue virus infection among urban, jungle, and rural populations in the Amazon region of Peru

The first confirmed outbreak of dengue fever in Peru occurred during 1990 in Iquitos, a city of approximately 300,000 residents in the Amazon region. Because of the apparent establishment of endemic transmission of this mosquito-borne viral disease following the outbreak, epidemiologic studies were initiated in 1992. Blood specimens and data on demographic, environmental, and medical history factors were collected from volunteers in an urban sector of Iquitos, in a rural area on the outskirts of Iquitos, and in three nearby jungle communities. A follow-up blood specimen was obtained approximately one year later from a sample of subjects. Sera were tested for dengue IgG antibody by an enzyme-linked immunosorbent assay, and specificity was verified using a plaque-reduction neutralization test. Dengue antibody prevalence was 66% in the urban population, 26% in the rural population, and 32-67% in the three jungle areas. A significant association was found between age and antibody prevalence, with a steady increase in prevalence from 18% among subjects less than five years of age to greater than 90% for subjects more than 50 years old. Increased antibody prevalence also was associated with urban and jungle residence and with a piped source of household drinking water. Seroconversions were documented in four of five surveyed communities. These results indicate that dengue virus transmission continues in and around Iquitos and suggest that transmission also occurred prior to the 1990 epidemic.

Functional significance of loops in the receptor binding domain of Bacillus thuringiensis CryIIIA delta-endotoxin

Analysis of the three surface loops in domain II of Bacillus thuringiensis CryIIIA delta-endotoxin has been carried out to assess their role in receptor binding and toxicity. Site-directed mutagenesis was used to convert loop residues to alanine and the mutant proteins were analyzed for structural stability, toxicity to beetle larvae (Tenebrio molitor), binding to receptors on T. molitor brush border membrane vesicles (Tm-BBMV) and insertion into BBMV, as measured by irreversible membrane receptor binding. This study demonstrates the functional significance of loops for binding and insertion. Alanine replacements in loop I resulted in disruption of receptor binding or structural instability. The double mutation, Y350A, Y351A, could be suppressed by replacing a nearby R345 with alanine, and the resultant mutant protein also showed reduced receptor binding. Substitution of N353 and D354 in loop I with alanine residues caused the loss of binding ability and toxicity. A loop II double mutant, P412A, S413A, had no effect on binding or toxicity. A block mutation of loop III residues to alanine had the effect of reducing receptor binding while concomitantly increasing toxicity by 2.4-fold. We compared this up-mutant to wild-type toxin in each step of physiological processing of protoxin: solubility, proteolytic activation, and insertion into the Tm-BBMV. The loop III block mutant showed increased membrane insertion, but was similar to wild-type toxin in other parameters. These results reveal that loop I and loop III in domain II of CryIIIA delta-endotoxin are involved in receptor binding. In addition, the direct correlation between toxicity and irreversible binding of the loop III block mutant (despite the indirect relationship to reversible binding) suggests that loop III may play a role in membrane insertion.

Cyclic variation of Doppler power from whole blood under pulsatile flow

The echogenicity and Doppler power from whole blood under pulsatile flow have been found to vary during the flow cycle in previous studies both in vitro and in vivo. The present study was undertaken to better understand this phenomenon. Doppler power from whole blood under pulsatile flow was measured with a pulsed Doppler flowmeter as a function of the flow cycle, radial position and compliance of the vessel in a mock flow loop. It was found that the cyclic variation is more pronounced if the stroke rate is less than 56 beats/min and that the peak of the Doppler power from whole blood flowing near the center stream coincided with the peak of the flow velocity. However, it began to lead the velocity peak as the measurement site was moved away from the center stream. The lead increased as the radial distance was increased. The results also show that the compliance of the vessel can affect, to a certain extent, the magnitude of the cyclic variation. Results from intravascular Doppler measurements rule out the possibility that the cyclic variation is primarily due to the variation in attenuation caused by vessel wall during a flow cycle.

Detection and sequence analysis of a new herpesvirus-like agent in AIDS and non-AIDS Kaposi's sarcoma in Taiwan

A new herpesvirus-like DNA sequence (KSHV) has been recently identified in Kaposi's sarcoma from acquired immunodeficiency syndrome (AIDS) and non-AIDS patients. In order to verify the role of this new viral agent in Taiwan, a series of Kaposi's sarcoma specimens obtained from AIDS and non-AIDS patients in three medical centers representing different geographic locations of Taiwan were surveyed. A total of seven specimens from AIDS patients and 22 specimens from non-AIDS patients were tested for the presence of this herpesvirus-like agent by polymerase chain reaction (PCR) using the published Kaposi's sarcoma 330-233 primers. The tumor DNA was also tested for cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpes-virus type 6 (HHV-6). The Kaposi's sarcoma specimens from AIDS and non-AIDS patients were positive for KSHV except in one case. Only occasional specimens were positive for CMV and EBV, with a slightly higher positive rate for HHV-6 in AIDS and non-AIDS patients. Cloning and sequence analysis of the PCR products from two cases of Kaposi's sarcoma (one each for AIDS and non-AIDS) revealed only minor differences in this DNA sequence, as compared with the published data from north America. These results further support the assumption that this new KSHV is strongly associated with Kaposi's sarcoma in AIDS and non-AIDS patients in Taiwan.

Detection of an Epstein-Barr-virus variant in T-cell-lymphoma tissues identical to the distinct strain observed in nasopharyngeal carcinoma in the Taiwanese population

An EBV variant has been identified in NPC tissues in Taiwan. This EBV variant contains a point mutation in exon I of the LMP I gene. This mutation results in the loss of an XhoI site at nt 169,426, which is present in strain B95-8. In addition, this variant contains a 30-bp deletion in exon 3 of the gene. The recent demonstration of the prevalence of EBV-containing nasal and peripheral T-cell lymphoma in this region drove us to evaluate the presence of this NPC-EBV strain in 7 cases of T-cell lymphoma, as well as in 48 NPC tissues, 2 cases of Hodgkin's disease and I B-cell lymphoma. Four samples of normal lymph node tissue, 40 of normal nasopharynx tissue and 78 throat washings of healthy individuals were included for comparison. We used sequence-specific primers and the polymerase chain reaction (PCR) method to amplify LMP I gene fragments containing these variations. Mutations were then confirmed by restriction-enzyme digestion and the DNA sequencing analysis. Our results showed that 57 of 58 tumor-tissues samples were EBV-positive. Among them, 56, including 6 T-cell-lymphoma samples, belonged to the NPC strain. This strain of EBV was also present in 92% of EBV-positive normal nasopharynx tissues and in 84% of EBV-positive throat washings of the healthy individuals tested. These results suggest that the NPC-EBV strain is prominently present in Taiwan.

Evaluation of the severe combined immunodeficient (SCID) mouse as an animal model for dengue viral infection

Severe combined immunodeficient (SCID) mice reconstituted with human peripheral blood lymphocytes (hu-PBL) were evaluated as an animal model for demonstrating dengue (DEN) viral infection. Reconstituted mice (hu-PBL-SCID) that demonstrated successful engraftment by the presence of serum titers of human immunoglobulin (Ig) were inoculated intraperitoneally with DEN virus serotype 1 (DEN-1). Serial blood samples were taken postinoculation and assayed for virus in C6/36 cells. The identity of all viral isolates was confirmed by an immunofluorescence antibody assay using DEN-1 monoclonal antibody. A total of six experiments were performed using different procedures of reconstitution and infection, and in three of these experiments, DEN-1 virus was recovered from the hu-PBL-SCID mice. In the first successful experiment, DEN-1 virus was recovered on postinoculation day (PID) 24 from blood, spleen, thymus, and lung tissues of one of eight hu-PBL-SCID mice. A second group of eight hu-PBL-SCID mice were inoculated with human monocytes infected in vitro with DEN-1 virus. Virus was recovered from the blood of mice between PID 15 and 23, and from lung tissue of one of these mice. In a third experiment, seven SCID mice were treated initially with anti-asialo GM1 antibody to eliminate natural killer cells, and then were injected simultaneously with a mixture of hu-PBL and DEN-1 virus. Virus was demonstrated in the blood of one mouse on PID 38, and in another mouse on PID 8, 12, 20, 24, and 36.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the alpha 2-subunit of laminin correlates with increased cell adhesion and metastatic propensity

Previous studies have indicated that laminin from neoplastic cells of high tumorigenicity is less active in promoting cell adhesion than aminin from normal cells or tissues. In the present study, we tested the hypothesis that laminin of metastatic tumor cells differs from that of nonmetastatic cells. Accordingly, we determined the subunit composition of laminin in highly metastatic, ras-transformed cells (4R) and compared it with laminin produced by nonmetastatic cells transformed with ras plus E1a (RE4). Metastatic 4R cells produced three to four times more of the alpha 2-subunit of laminin than RE4 cells did. Furthermore, the highly metastatic human melanoma cells (1205 and A2058) made and secreted into the medium, laminin containing significantly more of the alpha 2-subunit than laminin from the highly tumorigenic but nonmetastatic melanoma WM793 or HT1080 fibrosarcoma cells. Using HT1080 cells, laminin (250 ng/well) from 4R cells showed more adhesion promoting activity (68%) than laminin from RE4 cells (39%). Similarly, laminin isolated from human placenta, which expresses both the alpha 1 beta 1 gamma 1 and alpha 2 beta 1 gamma 1 isoforms, promoted cell adhesion better (63%) than EHS laminin (26%), which contains only the former isoform, at 250 ng/well. In addition, both 4R and RE4 cells attached more efficiently to 4R laminin-coated substratum than to RE4 laminin at 0.3 and 0.6 microgram/well.(ABSTRACT TRUNCATED AT 250 WORDS)