Genetic variation in the VP7 gene of human rotavirus serotype 3 (G3 type) isolated in China and Japan

Sequence analysis of the VP7 gene was performed on twenty-one human isolates of serotype 3 related-rotavirus in China and Japan. The five Chinese isolates were found to be not similar to the 16 Japanese isolates and to SA11 (simian rotavirus). The Chinese isolates, especially CHW2 and CH-32, were different from the major serotype 3 human isolates. AU-1 and 02/92 which previously showed a wider spacing between RNA segments 10 and 11 by RNA polyacrylamide gel electrophoretic analysis, were more closely related to each other and could be differentiated from the other Chinese and Japanese isolates. For these reasons, serotype 3 viruses were considered to be intraserotypically more heterologous than serotype 1, 2 and 4 viruses.

Gamma delta T-cell help in responses to pathogens and in the development of systemic autoimmunity

Mice rendered deficient in alpha beta T-cells by single-gene knockout mutation show enhanced levels of autoantibody formation and even some symptoms of autoimmune disease. This is remarkable given that most experimental studies heretofore have indicated that the development of autoimmune disease is highly multigenic, requiring the complementary actions of multiple loci. The basis of the phenomenon in alpha beta T-cell-deficient mice appears to be the provision of help to B-cells by other cells, including gamma delta T-cells. Perhaps surprisingly, gamma delta T-cell help seems quite efficacious, particularly after infection, when it can culminate in the formation of germinal centers. Furthermore, two independent sets of studies reviewed here indicate that significant levels of self-reactive IgG can also be provoked by gamma delta T-cells independent of germinal center formation. The task ahead is to integrate this pathway into the physiologic immune responses to healthy individuals, immunocompromised individuals, and newborns.

[The epidemiological study on human cytomegalovirus infection of pregnant women and the maternal-fetal transmission in three Chinese metropolis]

OBJECTIVES

To analyze the state of human cytomegalovirus (HCMV) infection of pregnant women and the maternal-fetal transmission in three chinese metropolis, and to study the methods of early prenatal diagnosis for intrauterine infection.

METHODS

Enzyme linked immunosorbent assay (ELISA) technique was employed to screen HCMV specific antibodies in 5,015 pregnant women of different trimesters. From this cohort study, 301 cases of active infection were selected to detect HCMV DNA by polymerase chain reaction (PCR) technique in their appendages of fetus, blood and urine of neonates, as well as breast milk.

RESULTS

The overall HCMV infection rate was 88.93% in the three metropolis and they were 96.74% and 91.42% in Shenyang and Shanghai respectively, which were significantly higher than that (79.53%) in Wuhan. The active infection rate was 5.42% generally while they were 11.23% and 10.89% in Wuhan and Shenyang respectively, which were significantly higher than that in Shanghai. In addition, the active infection rate of women with history of abnormal pregnancy was significantly higher than that was of the control group (14.59% vs 3.70%). By PCR technique, the detective rate of HCMV DNA were 16.00% in chroionic villi of early pregnancy and 35.33% in amniotic fluid of mid-trimester, which were not significantly different from these in umbilical blood, placentea at delivery and neonatal blood.

CONCLUSIONS

In China, the HCMV infection rates during pregnancy varied in different regions. A majority of women at children bearing age had HCMV infection before pregnancies; the yertical transmission frequently occurs from the actively infected mother. ELISA combined with PCR techniques is a valuable method for early prenatal diagnosis of HCMV congenital infection.

T-cell alpha beta + and gamma delta + deficient mice display abnormal but distinct phenotypes toward a natural, widespread infection of the intestinal epithelium

Vertebrate immune systems contain T cells bearing either alpha beta or gamma delta T-cell antigen receptors (TCRs). alpha beta T cells perform all well-characterized T-cell effector functions, while the biological functions of gamma delta + cells remain unclear. Of particular interest is the role of gamma delta + cells during epithelial infections, since gamma delta + cells are commonly abundant within epithelia. Eimeria spp. are intracellular protozoa that infect epithelia of most vertebrates, causing coccidiosis. This study shows that in response to Eimeria vermiformis, mice lacking alpha beta T cells display defects in protective immunity, while mice lacking gamma delta + cells display exaggerated intestinal damage, apparently due to a failure to regulate the consequences of the alpha beta T cell response. An immuno-downregulatory role during infection, and during autoimmune disease, may be a general one for gamma delta + cells.

Physical and biological characteristics of the antitumor drug actinomycin D analogues derivatized at N-methyl-L-valine residues

The crystal structure of the DNA-actinomycin D (AMD) complex and a simple molecular modeling study indicated that AMD analogues derivatized at N-methyl-L-valine residues (fifth amino acid residue in the cyclic depsipeptide of AMD) could bind to DNA as strongly as the parent AMD. The analogues in which N-methyl-L-valine residues were replaced with L- and D-forms of N-methylvalines, N-methylthreonines, N-methylphenylalanies, N-methyltyrosines, and N-methyl-O-methyltyrosines have been totally synthesized. The characteristics of binding of the analogues to various DNAs including DNA-1 [d(TATATATGCATATATA)], DNA-2 [d(TATATACGCGTATATA)], DNA-3 [d(ATATATAGCTATATAT)], and DNA-4 [d(ATATATGGCCATATAT)] have been examined by using visible absorption spectrum methods. The association constants calculated from the absorption spectra indicate that the modifications of the N-methyl-L-valine residues in the AMD molecule do affect the DNA binding characteristics of the analogues. The L-aromatic analogues bind slightly better than the L-aliphatic analogues except for binding to DNA-1 (-TGCA-), whereas the D-aliphatic analogues bind consistently better than the D-aromatic analogues. In the L-form analogues, the L-Tyr analogue has the highest overall association constant, whereas the D-Val analogue has the highest association constant among the D-form analogues. In spite of substitution of bulky aromatic groups, the D-aromatic analogues bind to the DNA-1 quite well. However, D-aromatic analogues have significantly reduced their binding capacities to the other DNAs, indicating that the substitution of the D-aromatic residues creates a unique four-base sequence preference (-TGCA-). The RNA polymerase inhibitory activities of the AMD analogues in vivo have been examined using human cells (HeLa). All AMD analogues except for the L-Thr analogues severely inhibit RNA synthesis at relatively low drug concentrations. The D-Val, L-OMT, L-Phe, and D-Phe analogues inhibit RNA synthesis more strongly than the natural antibiotic (AMD itself).

Gamma delta T cell help of B cells is induced by repeated parasitic infection, in the absence of other T cells

BACKGROUND

gamma delta T cells, like alpha beta T cells, are components of all well-studied vertebrate immune systems. Yet, the contribution of gamma delta T cells to immune responses is poorly characterized. In particular, it has not been resolved whether gamma delta cells, independent of any other T cells, can help B cells produce immunoglobulin and form germinal centers, anatomical foci of specialized T cell-B cell collaboration.

RESULTS

TCR beta-/- mice, which lack all T cells except gamma delta T cells, routinely displayed higher levels of antibody than fully T cell-deficient mice. Repeated parasitic infection of TCR beta-/- mice, but not of T cell-deficient mice, increased antibody levels and induced germinal centers that contained B cells and monoclonal gamma delta cells in close juxtaposition. However, antibody specificities were more commonly against self than against the challenging pathogen. gamma delta T cell-B cell help was not induced by repeated inoculation of TCR beta-/- mice with mycobacterial antigens.

CONCLUSIONS

In the absence of any other T cells, gamma delta T cell-B cell collaboration can be significantly enhanced by repeated infection. However, the lack of obvious enrichment for antibodies against the challenging pathogen distinguishes gamma delta T cell help from alpha beta T cell help induced under analogous circumstances. The increased production of generalized antibodies may be particularly relevant to the development of autoimmunity, which commonly occurs in patients suffering from alpha beta T cell deficiencies, such as AIDS.

Internal mobility of reactive-site-hydrolyzed recombinant Cucurbita maxima trypsin inhibitor-V characterized by NMR spectroscopy: evidence for differential stabilization of newly formed C- and N-termini

The solution structure and internal dynamics of the reactive-site (Lys44-Asp45 peptide bond) hydrolyzed form of recombinant Cucurbita maxima trypsin inhibitor-V (rCMTI-V*) were characterized by the application of two-dimensional 1H-15N NMR methods to the uniformly 15N-labeled protein. The 1H-15N chemical shift correlation spectra of rCMTI-V* were assigned, and the chemical shift data were compared with those available for rCMTI-V [Liu, J., Prakash, O., Cai, M., Gong, Y., Huang, Y., Wen, L., Wen, J. J., Huang, J.-K., & Krishnamoorthi, R. (1996) Biochemistry 35, 1516-1524] and CMTI-V* [Cai, M., Gong, Y., Prakash, O., & Krishnamoorthi, R. (1995) Biochemistry 34, 12087-12094] for which three-dimensional solution structures have been determined. It was deduced that the solution structure of rCMTI-V* was almost the same as that of CMTI-V*. 15N spin-lattice and spin-spin relaxation rate constants (R1 and R2, respectively) and ¿1H¿-15N steady-state heteronuclear Overhauser effects were measured for the peptide NH units and arginine and tryptophan N epsilon H groups in rCMTI-V*, and the model-free parameters [Lipari, G., & Szabo, A. (1982) J. Am. Chem. Soc. 104, 4546-4559, 4559-4570] were computed. Most of the backbone of rCMTI-V* is found to be highly constrained (S2 = 0.85), including the N-terminal residues 3-6 (S2 = 0.77). Residues 39-44, forming the C-terminal fragment of the binding loop, exhibit increased mobility (S2 = 0.51); however, the N-terminal segment (residues 46-48) retains rigidity as in the intact form (S2 = 0.83). The S2 values, 0.78 and 0.59, respectively, of Arg50 and Arg52 side chain NHs provide evidence not only for the conservation of the Arg hydrogen-bonds with the binding loop segments but also for the difference in strength between them. This is consistent with the earlier observation made from a study of rCMTI-V at two different pHs and its R50 and R52 mutants [Cai, M., Huang, Y., Prakash, O., Wen, L., Dunkelbarger, S. P., Huang, J.-K., Liu, J., & Krishnamoorthi, R. (1996) Biochemistry 35, 4784-4794]. The dynamical results suggest the mainchain oxygen atom of Asp45 as the hydrogen bond acceptor of Arg50. Residues Trp9 and Trp54, which interact with many others in the protein scaffold and the binding loop region, respectively, remain rigid in the cleaved inhibitor with the S2 values of 0.84 and 0.71 determined for their respective N epsilon Hs. The internal dynamics of rCMTI-V* was compared with that of the noncovalent complex formed between the two fragments of reactive-site-hydrolyzed chymotrypsin inhibitor-2 from barley seeds [CI-2; Shaw, G. L., Davis, B., Keeler, J., & Fersht, A. R. (1995) Biochemistry 34, 2225-2233], another potato I family inhibitor that lacks the Cys3-Cys48 disulfide present in rCMTI-V*.

[Effects on fetal and infant's development of intrauterine cytomegalovirus infection]

OBJECTIVE

To study the early effects of fetal development and remote sequalae of mental development of infants after intrauterine human cytomegalovirus (HCMV) infection.

METHODS

Enzyme-linked immunoabsorbant assay (ELISA) were used for screening HCMV antibodies in the serum of 1419 pregnant women. HCMV DNA were examined by PCR in maternal blood, amniotic fluid and/ or umbilical blood for those with serum HCMV-IgM positive and some with HCMV negative. According to the results, group A (n = 53) included women with positive serum HCMV-IgM and HCMV DNA, and also positive HCMV DNA in amniotic fluid and/or umbilical blood: group B (n = 87) were women with positive serum HCMV-IgM and HCMV DNA but negative HCMV DNA in amniotic fluid and/or umbilical blood: group C (n = 34) served as control with all negative. The above 174 cases were carefully monitored for fetal development. Baley scales of infant development (BSID) were used to test both mental development index (MDI) and psychomotor development index (PDI) at 2-30 months after birth for babies in group A and C.

RESULTS

The occurrences of fetal intrauterine death, congenital malformation, fetal growth retardation and neonatal asphyxia were significantly higher in group A than that in group B and C (P < 0.05) and the average birth weight and height were also significantly lower in group A (P < 0.05). The mental development of infants in group A were remarkably slower than that of group C (P < 0.01).

CONCLUSION

Active HCMV intrauterine infection may cause congential infection, birth defects and mental retardation in childhood.

Murine lupus in the absence of alpha beta T cells

To investigate the possibility that non-alpha beta T cell-dependent mechanisms can induce systemic autoimmune disease, and to address the roles of alpha beta T cells in murine lupus, we analyzed lupus-prone MRL mice congenitally deficient in alpha beta T cells. Surprisingly, TCR-alpha-/- MRL mice developed several characteristics of human systemic lupus erythematosus, including hypergammaglobulinemia, autoantibodies against DNA and small nuclear ribonucleoproteins, and immune deposits in kidneys. These results, which contrast with past studies concluding that MRL autoimmunity requires CD4+ alpha beta T cells, demonstrate that non-alpha beta T cell-dependent mechanisms are capable of inducing lupus phenomena, and further suggest that MRL disease may consist of both alpha beta T cell-independent and alpha beta T cell-dependent mechanisms.

Murine lupus in the absence of alpha beta T cells

To investigate the possibility that non-alpha beta T cell-dependent mechanisms can induce systemic autoimmune disease, and to address the roles of alpha beta T cells in murine lupus, we analyzed lupus-prone MRL mice congenitally deficient in alpha beta T cells. Surprisingly, TCR-alpha-/- MRL mice developed several characteristics of human systemic lupus erythematosus, including hypergammaglobulinemia, autoantibodies against DNA and small nuclear ribonucleoproteins, and immune deposits in kidneys. These results, which contrast with past studies concluding that MRL autoimmunity requires CD4+ alpha beta T cells, demonstrate that non-alpha beta T cell-dependent mechanisms are capable of inducing lupus phenomena, and further suggest that MRL disease may consist of both alpha beta T cell-independent and alpha beta T cell-dependent mechanisms.

Germinal center formation, immunoglobulin class switching, and autoantibody production driven by "non alpha/beta" T cells

The production of class-switched antibodies, particularly immunoglobulin (Ig) G1 and IgE, occurs efficiently in T cell receptor (TCR) alpha-/- mice that are congenitally devoid of alpha/beta T cells. This finding runs counter to a wealth of data indicating that IgG1 and IgE synthesis are largely dependent on the collaboration between B and alpha/beta T cells. Furthermore, many of the antibodies synthesized in TCR alpha-/- mice are reactive to a similar spectrum of self-antigens as that targeted by autoantibodies characterizing human systemic lupus erythematosus (SLE). SLE, too, is most commonly regarded as an alpha/beta T cell-mediated condition. To distinguish whether the development of autoantibodies in TCR alpha-/- mice is due to an intrinsic de-regulation of B cells, or to a heretofore poorly characterized collaboration between B and "non-alpha/beta T" cells, the phenotype has been reconstituted by transfer of various populations of B and non-alpha/beta T cells including cloned gamma/delta T cells derived from TCR alpha-/- mice, to severe combined immunodeficient (SCID) mice. The results establish that the reproducible production of IgG1 (including autoantibodies) is a product of non-alpha/beta T cell help that can be provided by gamma/delta T cells. This type of B-T collaboration sustains the production of germinal centers, lymphoid follicles that ordinarily are anatomical signatures of alpha/beta T-B cell collaboration. Thus, non-alpha/beta T cell help may drive Ig synthesis and autoreactivity under various circumstances, especially in cases of alpha/beta T cell immunodeficiency.

Differential modulation of binding loop flexibility and stability by Arg50 and Arg52 in Cucurbita maxima trypsin inhibitor-V deduced by trypsin-catalyzed hydrolysis and NMR spectroscopy

The side chains of Arg50 and Arg52 iin Cucurbita maxima trypsin inhibitor-V (CMTI-V) anchor the binding loop to the scaffold region [Cai, M., Gong, Y., Kao, J.L-F., & Krishnamoorthi, R. (1995) Biochemistry 34, 5201-5211]. The consequences of these hydrogen-bonding and electrostatic interactions on the conformational flexibility and stability of the binding loop were evaluated by trypsin-catalyzed hydrolysis of CMTI-V mutants, in which each of the arginines was individually replaced with Ala, Lys, or Gln by genetic engineering methods. All mutants exhibited significantly increased vulnerability to the protease attack at many sites, including the reactive-site (Lys44-Asp45 peptide bond), with the R50 mutants showing much more pronounced effects than the R52 counterparts. For CmTI-V and the mutants studied, a qualitative correlation was inferred between binding loop flexibility and retention time on a reverse-phase high-pressure liquid chromatography C-18 column. The R50 mutants were found to be more flexible than the corresponding R52 versions. These results demonstrate that Arg50 contributes more to the stability and function of CMTI-V. The differing strengths of the hydrogen bonds made by Arg50 and Arg52 were characterized by determining the internal dynamics of their side chains at pH 5.0 and 2.5: 15N NMR longitudinal and transverse relaxation rates and 15N-1H nuclear Overhauser effect (NOE) enhancements were measured for the main-chain and side-chain NH groups in 15N-labeled recombinant CMTI-V (rCMTI-V) and the model-free parameters [Lipari, G., & Szabo, A.(1982) J. Am. Chem. Soc. 104, 4546-59; 4559-4570] were calculated. At both pH 5.0 and 2.5, the arginines at positions 26, 47, 58 and 66 are found to be highly mobile, as the caluculated general order parameters, S2 values, of their NepsilonH groups fall in the range 0.03-0.18. The corresponding values for Arg50 amd Arg52 are 0.73 and 0.63, respectively, at pH 5.0, thus confirming that the two arginines are rigid and hydrogen bonded. At pH 2.5, these hydrogen bonds are still retained with Arg50 appearing to be more restrained (S2 = 0.71) than Arg52 (S2 = 0.56). This is consistent a greater contribution by Arg50 to the conformational stability of the reactive-site loop in CMTI-V. The results also indicate that the Arg50 and Arg52 side chains are not hydrogen-bonded to carboxylate groups, which would be protonated at pH 2.5 and, hence, unavailable for hydrogen-bonding interactions. The overall folding of rCMTI-V appears not to be significantly affected by the pH change, as indicated by comparisons of 1H and 15N chemical shifts, sequential NOE cross-peaks, and S2 values of the backbone atoms, and the conserved side-chain dynamics of Trp9 and Trp54--residues that are involved in hydrophobic and hydrogen-bonding interactions with others in the protein core and the binding loop, respectively.

Solution structure and backbone dynamics of recombinant Cucurbita maxima trypsin inhibitor-V determined by NMR spectroscopy

The solution structure of recombinant Cucurbita maxima trypsin inhibitor-V (rCMTI-V), whose N-terminal is unacetylated and carries an extra glycine residue, was determined by means of two-dimensional (2D) homo and 3D hetero NMR experiments in combination with a distance geometry and simulated annealing algorithm. A total of 927 interproton distances and 123 torsion angle constraints were utilized to generate 18 structures. The root mean squared deviation (RMSD) of the mean structure is 0.53 A for main-chain atoms and 0.95 A for all the non-hydrogen atoms of residues 3-40 and 49-67. The average structure of rCMTI-V is found to be almost the same as that of the native protein [Cai, M., Gong, Y., Kao, J.-L., & Krishnamoorthi, R. (1995) Biochemistry 34, 5201-5211]. The backbone dynamics of uniformly 15N-labeled rCMTI-V were characterized by 2D 1H-15N NMR methods. 15N spin-lattice and spin-spin relaxation rate constants (R1 and R2, respectively) and [1H]-15N steady-state heteronuclear Overhauser effect enhancements were measured for the peptide NH units and, using the model-free formalism [Lipari, G., & Szabo, A. (1982) J. Am. Chem. Soc. 104, 4546-4559, 4559-4570], the following parameters were determined: overall tumbling correlation time for the protein molecule (tau m), generalized order parameters for the individual N-H vectors (S2), effective correlation times for their internal motions (tau e), and terms to account for motions on a slower time scale (second) due to chemical exchange and/or conformational averaging (R(ex)). Most of the backbone NH groups of rCMTI-V are found to be highly constrained ((S2) = 0.83) with the exception of those in the binding loop (residues 41-48, (S2) = 0.71) and the N-terminal region ((S2) = 0.73). Main-chain atoms in these regions show large RMSD values in the average NMR structure. Residues involved in turns also appear to have more mobility ((S2) = 0.80). Dynamical properties of rCMTI-V were compared with those of two other inhibitors of the potato I family--eglin c [Peng, J. W., & Wagner, G. (1992) Biochemistry 31, 8571-8586] and barley chymotrypsin inhibitor 2 [CI-2; Shaw, G. L., Davis, B., Keeler, J., & Fersht, A. R. (1995) Biochemistry 34, 2225-2233]. The Cys3-Cys48 linkage found only in rCMTI-V appears to somewhat reduce the N-terminal flexibility; likewise, the C-terminal of rCMTI-V, being part of a beta-sheet, appears to be more rigid.

CD8 T cell clones from young nonobese diabetic (NOD) islets can transfer rapid onset of diabetes in NOD mice in the absence of CD4 cells

T cells play an important role in the pathogenesis of diabetes in the nonobese diabetic (NOD) mouse. CD8 cytotoxic T cell lines and clones were generated from the lymphocytic infiltrate in the islets of Langerhans of young (7-wk-old). NOD mice by growing them on (NOD x B6-RIP-B7-1)F1 islets. These cells proliferate specifically to NOD islets and kill NOD islets in vitro. The cells are restricted by H-2Kd, and all bear T cell antigen receptor encoded by V beta 6. When these CD8 T cell lines and clones are adoptively transferred to irradiated female NOD, young NOD-SCID, and CB17-SCID mice, diabetes occurs very rapidly, within 10 d of transfer and without CD4 T cells.

[The electron microscopic observation of the effect of monoclonal antibody on the form and structure of mutans streptococci OMZ176]

The effect of monoclonal antibody on the form and structure of Mutans Streptococci OMZ176 was studied. The result showed that a great number of Mutans Streptococci OMZ176 was agglutianated after treating with monoclonal antibody prepared by a cell wall protein antigen (molecular weight 220 kd) of Mutans Streptococci OMZ176. Bacterial cells were swollen obviously. The gap between cell wall and cytoplasmic was widened. The electronic density of cell plasm was greatly decreased.

Genetic variation in VP7 gene of human rotavirus serotype 2 (G2 type) isolated in Japan, China, and Pakistan

Sequence analysis of the gene encoding the major neutralization glycoprotein (VP7) was performed on sixteen human isolates of serotype 2 of rotavirus in Japan, China, and Pakistan and their genetic variations were examined. Comparative studies of their nucleotide and deduced amino acid sequences between the sixteen isolates and the HU5 strain revealed an overall homology of more than 94%. A higher degree of homology in nucleotides was observed among the sixteen isolates than between HU5 and the isolates. A total of thirteen amino acid residues frequently converted to another amino acid. Out of the thirteen, five amino acid residues belonging to the major neutralizing epitope regions (C, E, and F in this communication) converted frequently. From the amino acid sequences three subtypes, subtype 1, subtype 2, and intermediate, were suggested to be classified as previously reported for serotype 1 (Xin et al, Virology, 1993, 197: 813-816).

Experimental studies of the effect of Forskolin on the lowering of intraocular pressure

PURPOSE

To determine the effect of domestic Forskolin on lowering of intraocular pressure (IOP) in rabbits.

METHODS

Measure the normal IOP and ocular hypertension by water load in rabbits using Perkins tonometer. Measure the adenylate cyclase (AC) activity by Ho & Sutherland's method.

RESULTS

The results show that Forskolin significantly lowered the normal IOP of rabbits and blocked the ocular hypertension induced by water load in rabbits (P < 0.01). The maximum decrease value of 2%, 1% and 0.5% of the Forskolin was 0.59, 0.36 and 0.19 kPa (1kPa = 7.5 mmHg), which showed the noticeable dose-effect relationship. Topical ocular application of Forskolin lowered IOP in half an hour, reached to a peak in 2-3 hours and remained significantly for 10 hours. The pupillary diameter did not change when IOP was reduced. The Forskolin had potent stimulative properties to AC. The greater the ability of the Forskolin to stimulate AC, the stronger the effect of IOP lowering.

CONCLUSIONS

The Forskolin had the effect on lowering the IOP of rabbits. The mechanism of IOP reduction by Forskolin is related to its AC activation.

[Uteroplacental blood flow monitoring by color Doppler flow imaging in pregnancy induced hypertension]

The uteroplacental blood flow was monitored using color Doppler flow imaging (CDFI) in 31 cases of pregnancy induced hypertension (PIH) and 71 cases of normal pregnancy. At the same time the values of serum estriol (E3), human placental lactogen (hPL), thromboxane (TXB2), 6-KP and TXB2/6-KP ratio were measured. The results showed that time average velocity (TAV) and volume of blood flow (Q) of uterine and umbilical arteries in PIH cases were much lower than those in normal pregnant women and fetuses (P < 0.05). After treatment with magnesium sulfate and qingxintong there was a marked improvement in placental blood flow. TAV and Q of uterine and umbilical arteries was also increased (P < 0.05). In PIH cases the E3 and hPL levels were much lower, while the ratio of TXB2/6-KP was significantly higher than that in normal pregnancy. Using CDFI to observe the velocity and volume of uteroplacental blood flow can monitor the blood supply of uterus and placenta. It is a valuable predictive index of fetal and placental function.

Validity of the three-column theory of thoracolumbar fractures. A biomechanic investigation

STUDY DESIGN

This study validated the three-column theory of fractures by correlating the multidirectional instabilities and the vertebral injuries to each of the three columns, using a biomechanic trauma model.

OBJECTIVES

The objective was to validate the three-column theory as applied to the thoracolumbar fractures.

SUMMARY OF BACKGROUND DATA

The widely used three-column theory of fractures for classification and evaluation was based on retrospective analysis of radiographs. No biomechanic study, using realistic spinal fractures and multidirectional instability measurements, was available.

METHODS

Using 16 fresh cadaveric thoracolumbar human spine specimens, two groups of burst fractures were produced by either simple axial compression or flexion-compression, using a high-speed trauma model. Multidirectional flexibility was measured before and after the trauma, thus quantifying the instability of the burst fracture. Computed tomography scans were taken after the fracture, and a newly developed injury scoring scheme quantified the injuries to the anterior, middle, and posterior columns. Statistical correlations were obtained between the flexibility parameters and injuries to each of the three columns.

RESULTS

In the axial compression group, the middle column injury, compared with the other two columns, showed the highest correlations to eight of the nine flexibility parameters (average R2 = 0.77). In the flexion-compression group, again the middle column injury showed the highest correlations to eight of the nine flexibility parameters (average R2 = 0.85).

CONCLUSIONS

The results of this study supported the three-column theory of the thoracolumbar fractures and bolstered the concept of the middle column being the primary determinant of mechanical stability of this region of the spine.

Changing the inhibitory specificity and function of Cucurbita maxima trypsin inhibitor-V by site-directed mutagenesis

Cucurbita maxima trypsin inhibitor-V (CMTI-V) is also a specific inhibitor of human blood coagulation factor beta-factor XIIa. A recombinant version of CMTI-V has allowed probing of roles of individual amino acid residues including the reactive site residue, lysine (P1), by site-directed mutagenesis. The K44R showed at least a 5-fold increase in inhibitory activity toward human beta-factor XIIa, while there was no change toward bovine trypsin. This result demonstrates that beta-factor-XIIa prefers an arginine residue over lysine residue, while trypsin is non-specific to lysine or arginine in its binding pocket. On the other hand, the specificity of CMTI-V could be changed from trypsin to chymotrypsin inhibition by mutation of the P1 residue to either leucine or methionine (K44L or K44M).

Dynamic canal encroachment during thoracolumbar burst fractures

In the burst fractures seen clinically, often poor correlation exists between the neurological deficit and the canal encroachment measured on post-trauma radiographic images. The purpose of the present study was to determine whether the dynamic canal encroachment during the trauma is greater than the static canal encroachment posttrauma. We successfully produced burst fractures in nine of 15 fresh human cadaveric thoracolumbar spine specimens (T11-L1). The specimens were incrementally impacted in a high-speed trauma apparatus until fracture occurred. During the trauma, dynamic canal encroachments were measured using three specially designed transducers placed in the canal at the levels of the superior end-plates of the T12 and L1 and the T12/L1 disk. After the trauma, residual static spinal canal encroachments were measured from the radiographs of the specimens that were prepared with 1.6-mm diameter steel balls lining the canal in the midsagittal plane. We found that the average canal diameter was 16.6 +/- 1.3 mm and the static canal encroachment was 18.0% of the canal diameter. The corresponding dynamic canal encroachment was 33.3%. Thus, the dynamic canal encroachment was 85% more than the static measurement. The clinical significance of this study lies in providing awareness to the clinician that the dynamic canal encroachment is significantly greater than the static canal encroachment seen on posttrauma radiographs or computed tomography scans. The finding may also explain the clinical observation of poor correlation between the canal encroachment measured radiographically and the neurological deficit.