Studies on the ossification of compound transplantation of porous TCP ceramics and bone marrow

Following the culture of human red marrow with porous TCP ceramics in vitro, a large amount culturing marrow cells adhered well to the surface and inner wall of TCP ceramics and spread well over the dish bottom 4 weeks after cultivation. After the compound transplantation of porous TCP ceramics with red marrow into quadriceps femoris muscle of rabbits, a huge amount of new bone and marrow formed in these sites on and in the ceramics 4 weeks after transplantation. These results showed an excellent biocompatibility between TCP ceramics and marrow and an excellent osteogenic effect in the compound transplantation. The mechanism of ossification and clinical significance about the compound transplantation were discussed.

Changes in bone noncollagenous proteins and bone mineral loss in lumbar vertebrae of tail-suspended rats

The purpose of the study is to clarify whether the noncollagenous proteins play a role in bone mineral loss and whether the quality of osteocalcin (OC) is deteriorated in simulated weightlessness. Noncollagenous proteins, such as OC and albumin, have been shown to be effective in promoting bone mineralization. In this study, the contents of OC, albumin, and mineral in the third lumbar vertebra (L3) were determined in rats suspended by tail for 21 days. The concentration of serum-immunoreactive osteocalcin (irOC) were also measured before and after adsorption to hydroxylapatite. The results showed that the contents of mineral, osteocalcin, and albumin in L3 were significantly decreased in suspended rats. The concentration of serum irOC and serum irOC with a high affinity to hydroxylapatite (irOCbound) were significantly decreased, but the low affinity (irOCfree) remained unaffected. The data suggest that the mineral loss in L3 of suspended rats is related to the decreased contents of osteocalcin, and albumin in bone mass. The incomplete gamma-carboxylation of osteocalcin in suspended rats is also one of the important causes of bone loss.

[Effects of octacosanol in food physiological parameters in tail-suspended rats]

The purposes of the experiment were to observe the physiological effects of octacosanol in food on tail-suspended rats and to investigate the possibility of using octacosanol in health food for astronauts. 24 male Wistar rats were randomly divided into free action control, tail-suspension and tail suspension plus octacosanol (TSO) groups. Octacosanol was emulsified into water by supersound and given to TSO rats with a dosage of 25 mg/kg wt d. The results showed that octacosanol elevated the weight of thymus, improved biomechanical properties of the femur and improved membrane fluidity of red blood cell. It suggests that octacosanol can counteract some effects of simulated weightlessness on rats. Therefore, octacosanol may be added to natural foods to benefit the health of cosmonauts.

[Studies on all-spectrum analysis for X-ray diffraction of Chinese herbal medicine calculus bovis]

Investigation on famouse Chinese herbal medicine-Niu huang (calculus bovis) was carried out by all-spectrum X-ray diffraction analysis. Diffraction spectrums, as well as the specific symboling peaks of calculus bovis, artificial bezoar, bile ductstone, human gallstone and hog gallstone, were recognized. The error distribution curves of d-delta d for specific symboling peaks was also obtained by calculation under diffrent testing conditions, by which we identified successfully three samples provided by a pharmaceutical factory. This article shows that all-spectrum X-ray diffraction analysis can be used to identify Chinese traditional crude drug, and provides for morphological and microscopical study.

A unified approach to a class of stochastic carcinogenesis models

Survival and hazard functions play a pivotal role in carcinogenesis modeling. This paper provides a unified approach to computing these two quantities by classifying a large class of carcinogenesis models from a computational point of view, and prescribes specific computational recipes according to this classification.

[Study on the inclusion compound of phyllostachysin A and DMF]

The crystal structure of inclusion compound phyllostachysin A[1] and DMF, C20H26O6.C3H7ON, was determined by X-ray diffraction. A colorless block crystal with dimensions of 0.6 x 0.6 x 0.8 mm was used for analysis. It shows orthorhombic, and it's space group is P2(1)2(1)2(1) with a = 10.895(3), b = 13.237(2), c = 15.373(3) A, V = 2217.0(3) A3 Z = 4, Dc = 1.302 g cm-3. Direct method was applyed to determine the structure, and the parameters were refined by least square method. The final Rf factor is 0.060 and Rw = 0.083. The result shows that the crystal is formed by Phyllostachysin A and DMF by inclusion interaction.

[HBsAg autologous red cell agglutination assay]

Three lot of HBsAg autologous red cell agglutination kits (ARCA kit) have been qualified in lab, clinical trial and the stability confirmation have been performed. The sensitivity of the kits is 1ng/ml HBsAg. A, B, O, AB type of peripheral blood or antiagglutinated specimens can be used for assay. No Holk effect has been found. The repeated rate of 10 samples assayed for five times reached 100%. The specimens collected from HAV, HCV, Schistosoma Japonicum infected patients or RF positive patients do not interfere the test. The specificity of the kits is very high. 1712 clinical specimens were inspected comparing with the EIA kits in market. The relativity between the two methods is 0.985. 18 of the 26 specimens which two methods did not accord with each other have been confirmed. The false positive and missing detected for ARCA kits is 1, 3 and for EIA kits are 6, 8 respectively. ARCA kits are stable in 4 degrees C and 22 degrees C for more than one year. The kits can stand in 35 degrees C, 45 degrees C for 45 and 10 days without losing activity respectively.

Determination of CAG repeat length in the androgen-receptor gene using frozen serum

OBJECTIVES

To determine CAG repeat length in exon one of the androgen-receptor gene, using frozen serum as a source of deoxyribonucleic acid (DNA).

METHODS

Samples from previously frozen serum samples were prepared for polymerase chain reaction (PCR) by heating thawed serum to 100 degrees C and subsequent centrifugation at 16,000 g. Three microliters of supernatant were added to the PCR in combination with primers flanking the CAG repeat in exon one of the human androgen-receptor gene. After 35 cycles, the PCR amplicons were electrophoresed on an agarose gel, excised, purified, and sequenced. CAG repeat length was directly determined from DNA sequencing gels.

RESULTS

Amplified DNA fragments were obtained after PCR from 140 of the 200 specimens examined to date. The DNA amplicon was successfully sequenced in 111 samples derived from 104 individuals. Within this group, the androgen receptor CAG repeat length varied from 11 to 27. The median CAG repeat length was 21; the lower and upper quartiles were 18 or less and 23 or more, respectively. Results were consistent in each case that CAG repeat length was repetitively determined.

CONCLUSIONS

The establishment of a methodology to determine androgen-receptor gene CAG repeat length from frozen serum samples opens multiple new opportunities to explore the potential clinical significance of this genetic polymorphism.

[Comparison of changes of bone mass, parathyroid hormone and calcitonin between two animal models of bone loss]

The changes in bone mass, blood parathyroid hormone (PTH) and calcitonin (CT) between rats suspended for 14 and 21 days, simulated weightlessness, and rats ovariectomized (OVX) for 30 and 60 days were observed. The results revealed that mineral density of T6 and L3 was significantly increased in rats suspended for 14 days. T6 mineral density was also significantly increased in rats suspended for 21 days, but L3 mineral density was significantly decreased. T6 mineral density had no change in OVX rats, but L3 mineral density was significantly decreased in them both for 30 and 60 days. Mineral content at proximal 1/3 of femur shaft was significantly decreased in rats suspended for 14 and 21 days, and in rats OVX for 60 days. Bone biomechanical properties of suspended rats were more seriously deteriorated than that in OVX rats. There was no change in blood PTH, but CT was significantly increased in rats suspended for 14 and 21 days. Blood PTH and CT were significantly decreased in rats OVX for 30 and 60 days. The results indicate that the mineral redistribution and bone loss are presented in trabecular bone of suspended rats, but not in OVX rats. The deterioration of bone quality was more seriously in suspended rats than that in OVX rats. Both the cortical and trabecular bone in the two models were affected.

Effect and clinical value of splanchnic nerve block of hemodynamics in ACST

The condition of acute cholangitis of severe type (ACST) develops very rapidly and the prognosis is poor. The main clinical feature is that there is an obvious dynamic variation, which is the principal factor for the early occurrence of shock and death. In this study the Japanese long ear rabbits were used and biliary tract pressure increasing and splanchnic nervous plexus blocking experiments were conducted. Our results indicate that 0.6% of lidocaine can be used to block the right celiac plexus. It can avoid the decrease of blood pressure due to the pressure increase of the biliary tract, and the decrease of blood pressure due to the pressure increase of the biliary tract can be corrected by local anesthesia. 8 cases in conformity with the ACST diagnostic standards received the right renal capsule block injection for the purpose of stopping the celiac plexus, 6 cases of whom had a return of blood pressure to various extent, suggesting that the splanchnic nervous activity in the occurrence of ACST is of great significance. The technique may provide a new approach for the clinical treatment of ACST.

Allelic variants of human TCR BV17S1 defined by restriction fragment length polymorphism, single strand conformation polymorphism, and amplification refractory mutation system analyses

Several human TCR BV gene subfamilies, including BV3, BV14, and BV17S1, are single member genes but are overutilized among activated CD4+ synovial T cells in the rheumatoid arthritis (RA). To define the role of these TCR BV genes in the pathogenesis of disease, it is critical to characterize the genomic organization and the allelic variations of these genes. In this study we describe allelic variations of BV17S1 defined by restriction fragment length polymorphism (RFLP), single strand conformation polymorphism (SSCP), and amplification refractory mutation system (ARMS) analyses. A single nucleotide replacement (C/T) results in an amino acid substitution (F/L) in the leader and distinguishes BV17S1*1 from BV17S1*2. This nucleotide substitution was found to create a BsmAI restriction enzyme recognition site in BV17S1*2. Therefore genotypic analyses can be performed either by the SSCP or RFLP method. The analyses of 75 unrelated individuals show that the frequency for allele BV17S1*1 is 52.7% and for allele BV17S1*2 is 47.3%. Both alleles are functionally expressed and are distributed within CD4+/CD8+ T cell subsets. Another point mutation in the CDR2 region of BV17S1, which results in the amino acid replacement of Gln by His, originally identified form a cDNA clone, has now been confirmed as an allele by ARMS analysis using genomic DNA preparations and designated to as BV17S1*3. Screening of this CDR2 related variant among normal populations indicates that this is a rare allele (1 of 75). Although this variant may be of functional significance, the genotypic analysis and functional studies are difficult due to the low frequency of BV17S1*3. In an attempt to define a correlation between BV17S1 allelic usage and susceptibility to RA, the germline distribution of BV17S1 alleles *1 and *2 has been examined in a small number of RA patients and no skewed usage has been identified.

Role of postreplicative DNA mismatch repair in the cytotoxic action of thioguanine

It is proposed here that the delayed cytotoxicity of thioguanine involves the postreplicative DNA mismatch repair system. After incorporation into DNA, the thioguanine is chemically methylated by S-adenosylmethionine to form S6-methylthioguanine. During DNA replication, the S6-methylthioguanine directs incorporation of either thymine or cytosine into the growing DNA strand, and the resultant S6-methylthioguanine-thymine pairs are recognized by the postreplicative mismatch repair system. Azathioprine, an immunosuppressant used in organ transplantation, is partly converted to thioguanine. Because the carcinogenicity of N-nitrosamines depends on formation of O6-alkylguanine in DNA, the formation of the analog S6-methylthioguanine during azathioprine treatment may partly explain the high incidence of cancer after transplantation.

[A histomorphometric study on the bone healing after oblique osteotomy of the mandibular ramus]

The paper deals with quantitative study of bone healing in goat after unilateral oblique osteotomy of the mandibular ramus. Bone histomorphometry combined with tetracycline bone labelling and gamma monophoton absorptiometry were used to assess the rate of the new bone formation and its degree of mineralization during the healing process. The result showed that if the articular capsule and the lateral pterygoid muscle were remained and attached, the quantity of new trabaculae and the rate of bone healing in the inferior part of proximal fragment were less than those in the superior part (P < 0.05). There was a bone healing delay in the inferior part of proximal fragment.

[A study on relationship between glutathione S-transferase mu gene deletion and senile cataract susceptibility]

OBJECTIVE

To study the relationship between glutathione S-transferase mu (GST mu) gene deletion and senile cataract (SC) susceptibility.

METHOD

Polymerase chain reaction (PCR) method was used to investigate the rates of GST mu gene deletion in 59 cases with SC and 112 healthy controls.

RESULTS

The rate of GST mu gene deletion in cases with SC was 69.5% which was significantly higher than that of the controls, 50.9% (P < 0.05). An analysis stratified by smoking and nonsmoking showed that GST mu gene deletion rate in smoking subjects with SC was higher. Because of the small sample size of this study, although the rate of GST mu gene deletion in smoking subjects with SC has reached 72.4%, that is not significantly different from that of the controls statistically (P > 0.05).

CONCLUSION

SC correlates with GST mu gene deletion and GST mu gene deletion is one of the hereditary factors for susceptibility to SC.

Computational screening of combinatorial libraries

We first review existing computational methods with an intrinsic combinatorial feature, then describe a new computational method for screening combinatorial libraries using a recently developed multicopy sampling technique. The new method differs from the existing ones in that it can be used to screen simultaneously an entire library of molecules, instead of the individual molecules in a library. As an example, we have applied the method to study site-directed amino acid substitutions in a protein. After two rounds of library screening, we identified the energetically most stable substitutions along with their optimal conformations from all natural amino acids. In principle, the method is generally applicable to study ligand-host systems.

Risk assessment of nongenotoxic carcinogens based upon cell proliferation/death rates in rodents

Increased cell proliferation increases the opportunity for transformations of normal cells to malignant cells via intermediate cells. Nongenotoxic cytotoxic carcinogens that increase cell proliferation rates to replace necrotic cells are likely to have a threshold dose for cytotoxicity below which necrosis and hence, carcinogenesis do not occur. Thus, low dose cancer risk estimates based upon nonthreshold, linear extrapolation are inappropriate for this situation. However, a threshold dose is questionable if a nongenotoxic carcinogen acts via a cell receptor. Also, a nongenotoxic carcinogen that increases the cell proliferation rate, via the cell division rate and/or cell removal rate by apoptosis, by augmenting an existing endogenous mechanism is not likely to have a threshold dose. Whether or not a threshold dose exists for nongenotoxic carcinogens, it is of interest to study the relationship between lifetime tumor incidence and the cell proliferation rate. The Moolgavkar-Venzon-Knudson biologically based stochastic two-stage clonal expansion model is used to describe a carcinogenic process. Because the variability in cell proliferation rates among animals often makes it impossible to detect changes of less than 20% in the rate, it is shown that small changes in the cell proliferation rate, that may be obscured by the background noise in rates, can produce large changes in the lifetime tumor incidence as calculated from the Moolgavkar-Venzon-Knudson model. That is, dose response curves for cell proliferation and tumor incidence do not necessarily mimic each other. This makes the use of no observed effect levels (NOELs) for cell proliferation rates often inadmissible for establishing acceptable daily intakes (ADIs) of nongenotoxic carcinogens. In those cases where low dose linearity is not likely, a potential alternative to a NOEL is a benchmark dose corresponding to a small increase in the cell proliferation rate, e.g., 1%, to which appropriate safety (uncertainty) factors can be applied to arrive at an ADI.

Prevention and management of related complication due to laparoscopic operation: pneumothorax, pneumomediastinum and subcutaneous emphysema

Essential prerequisite of laparoscopic operation is establishing and maintaining pneumoperitoneum with a certain pressure. But under certain circumstances CO2-gas insufflating could induce pneumothorax, pneumomediastinum and subcutaneous emphysema during the operation. to probe the mechanism of the above complications. 2 typical cases were reported with attempt to probe the mechanism of the development of such applications. We believe that high intra-abdominal pressure during operation is the primary cause of the complications. The essentials of prevention and management of such complications were proposed.

Accuracy and reliability of the scaling-relaxation method for loop closure: an evaluation based on extensive and multiple copy conformational samplings

The accuracy and reliability of the recently proposed scaling-relaxation method for loop closure were examined by using extensive conformational sampling. For each of the eight heptapeptides chosen to represent a variety of protein conformations, 1,000-2,000 conformations were sampled. Each segment contained 14 rotatable backbone dihedral angles. The average root mean square deviations (RMSDs) between the predicted and the native conformations were 0.7 angstrom for the backbone and 1.2 angstroms for the side chain atoms. These predictions were substantially more accurate than the previous predictions (1.1 angstroms for the backbone and 2.2 angstroms for the side chain atoms) of the same eight protein segments based on limited conformational sampling (100 conformations for each segment). Large prediction errors mostly occurred at polar and surface side chains that are unlikely to have any meaningful conformation. Moreover, the reliability of seven of the eight predictions was demonstrated with their energy-RMSD and stability-RMSD correlations of the low-energy conformations, where the conformational stability was estimated by using the multiple copy simultaneous sampling method.

Rapid and repetitive plant regeneration in sweetpotato via somatic embryogenesis

An efficient in vitro plant regeneration system characterized by rapid and continuous production of somatic embryos using leaf and petiole expiants has been developed in sweetpotato [Ipomoea batatas L. (Lam.)]. The optimal somatic embryogenic response was obtained in the genotype PI 318846-3 with a two-step protocol: (1) stage I-incubation of expiants in the dark for 2 weeks on Murashige Skoog (MS) medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) (2.5 mg/l) and 6-benzylaminopurine (0.25 mg/l) and, (2) stage II-culture in the light on MS medium with abscisic acid (ABA) (2.5 mg/l). The addition of ABA was critical for enhanced production of somatic embryos. Secondary somatic embryos were produced from the primary embryos cultured on MS medium with 2,4-D at 0.2 mg/l. The somatic embryos were converted into normal plantlets when cultured on basal MS medium. Upon transfer to soil, plants grew well and appeared normal with no mortality. The system of somatic embryogenesis described here will facilitate tissue culture, germplasm conservation and gene transfer research of sweetpotato due to its rapidity (6 to 10 weeks), prolific plant production by direct embryogenesis, ease of secondary somatic embryo production and reproducibility.

Fluorescent indicators give biased estimates of intracellular free calcium change in aggregating platelets: implication for studies with human von Willebrand factor

The ratiometric fluorescent indicators Fura-2 and Indo-1 are considered optimal probes for monitoring intracellular free calcium concentration ([Ca2+]i). Unique problems arise, however, in studying [Ca2+]i changes induced in platelets by von Willebrand factor (vWF). Binding of native multimeric vWF causes extensive platelet aggregation, and is reported to evoke a gradual [Ca2+]i increase. the present investigation examined the reliability of platelet [Ca2+]i measurements in these circumstances. Ristocetin-mediated binding of vWF to human platelets promoted a slow rise in Fura-2 fluorescence ratio. Fura-2 extrusion contributed substantially to this rise, unless blocked by probenecid. Despite this precaution, the platelets were invariably contaminated slightly with extracellular indicator. As aggregation progressively reduced the number of platelets in the spectrofluorometer beam, through settling of the larger aggregates, such extracellular Fura-2 contributed proportionately more to the observed fluorescence. This extraneous signal accounted completely for the fluorescence ratio increase, and apparent [Ca2+]i rise, in response to native multimeric vWF. The same problem arose with Indo-1, whereas the single wavelength indicator Fluo-3 showed the opposite pattern of apparent [Ca2+]i changes. Thus, none of these indicators provides reliable data on [Ca2+]i signals in aggregating platelets. Use of a dimeric form of vWF eliminated the problem of platelet aggregates settling out of suspension, but also virtually abolished the [Ca2+]i increase. These observations may explain some of the inconsistencies among previous investigations of vWF-induced calcium signaling. Moreover, similar problems may arise in studies with other adhesive proteins.

Glucose regulation of glucose transporters in cultured adult and fetal hepatocytes

GLUT2 is the major glucose transporter of adult hepatocytes. In vivo, membrane GLUT1 is localized to a ring of perivenous cells and increases slightly after fasting or insulin deprivation. GLUT1 also increases in vitro after prolonged culture of isolated adult hepatocytes. We have previously shown that GLUT1 mRNA, protein, and activity are present in the rat fetal hepatocyte, and that both GLUT1 and GLUT2 are important for the pattern of glucose transport in the fetal hepatocyte. We tested the hypothesis that the hypothesis that the postnatal increase in circulating glucose is one of the regulators of the changed pattern of GLUT1 and GLUT2 in the hepatocyte after the fetal to neonatal transition. Fetal and adult rat hepatocytes were cultured for 45 hours in supplemented Dulbecco's modified Eagle's medium at glucose concentrations of 1, 8.3, or 30 mmol/L. Culture at 8.3 and 30 mmol/L glucose diminished GLUT1 mRNA levels were lower in adult versus fetal hepatocyte cultures at 8.3 and 30 mmol/L (P < .05). Similarly, GLUT1 protein levels were significantly diminished in hepatocytes cultured at higher medium glucose (P < .05 for fetal cells at 30 v 1 mmol/L; P < .05 for adult cells at 8.3 and 30 v 1 mmol/L). GLUT2 mRNA abundance was enhanced by medium glucose in adult hepatocytes (P < .05 at 8.3 and 30 v 1 mmol/L) and was unchanged by medium glucose in fetal hepatocytes. In contrast, GLUT2 protein level was unchanged by medium glucose in adult hepatocytes, and was diminished at 30 mmol/L as compared with mmol/L glucose in fetal hepatocytes (P < .05). In confirmation of these findings, uptake of 2-deoxyglucose (2-DOG) by fetal hepatocytes was significantly diminished after culture in 8.3 or 30 mmol/L glucose versus 1 mmol/L glucose (P < .05 and < .01, respectively). These studies confirm that the fetal hepatocyte glucose transporter pattern could be maintained in part by low fetal portal glucose levels. However, the resistance of the fetal hepatocyte glucose transporter pattern as compared with that of the adult hepatocyte to the effects of hyperglycemia suggests additional undefined control mechanisms.

[Hemodynamic study of distal splenorenal shunt (DSRS)]

Color-flow Doppler sonography (FDS) was used for assessing the hemodynamic changes in 8 patients undergoing distal splenorenal shunt (DSRS). Results were compared with 14 patients with portal-azygos disconnection (PAD). It was found that 3 weeks after DSRS portal venous flow (PVF) decreased by 50%, and at least in some patients the reduction of the PVF was a continuous process during the period of two years in the DSRS group. The postoperative decrease in PVF in DSRS patients was in sharp contrast to that in PAD patients (P < 0.001), hence PAD is superior to DSRS in remaining satisfactory PVF.

On the MVK stochastic carcinogenesis model with Erlang distributed cell life lengths

This paper proposes extending the MVK carcinogenesis model by adopting the Erlang distribution for the life length of the intermediate cells. The investigation concentrates on the survival function and the mean value functions. The approach is basically numerical, making use of the Mathematica software system. The paper also provides a closed form expression for the survival function for a variation of the original MVK model, where all the model parameters are piecewise constants.

Design and properties of photocurable electroconductive polymers for use in biosensors

The authors report preparation of a new hydrophilic photocurable electroconductive polymer to be used as a matrix for an enzyme based biosensor. Polymers, prepared by radical terpolymerization, consisted of N,N-dimethylacrylamide (DMAA) as the water soluble part, m-azidostyrene (AzSt) as the photochemically active center to entrap an enzyme and to fix it on an electrode, and vinylferrocene (VFe) as the charge transfer mediator between an enzyme and an electrode. Ultraviolet light (UV) irradiation to the terpolymer coated on a carbon electrode produced a water swellable cross-linked polymer that was chemically fixed on a carbon electrode. Cyclic voltammetry on a hydrogelated electrode in a phosphate buffered solution exhibited single oxidation/reduction reproducibly, indicating that the formed conducting hydrogel was stable. An increase in VFe content and a decrease in AzSt content of a terpolymer resulted in larger electrochemical responses on normal pulse voltammetry. When glucose oxidase was immobilized in a hydrogel, a dose dependent electrochemical response to glucose was observed.

[Fine stereo structure for natural organic molecules, a preliminary study. II. Melting point influenced by structure factors]

Crystal structures of two compounds from Tripterygium wilfordii Hook f. have been determined by X-ray diffraction method. Structure factors influencing melting point of solid state have been analysed. Crystal class (or space group), recrystallization solvent, force between molecules and fine changes of molecular structures will all cause melting point changes of crystal substance.

[The study of GST mu gene deletion as the hereditary marker for susceptibility to lung cancer]

A total of 175 lung cancer patients and 104 controls were detected for GST mu gene using PCR technique. The results showed that the GST mu gene deletion rate in lung cancer patients was 71.4%, which was significantly higher than the controls, 51.9%. Analysis according to pathological classification of lung cancer indicated that the GST mu gene deletion rate in all three kinds of pathological types-squamous, adenocarcinoma and small cell carcinoma, were markedly higher than that of controls, especially for small cell carcinoma (the deletion sate is 77.5%). The frequency of GST mu gene was not associated with smoking in both groups, but the higher deficiency rate was found in the low age group of lung cancer patients, showed 85.3% compared to the high age group, 68.1%. All the results showed that GST mu gene deletion may be an important host hereditary marker for susceptibility to lung cancer.

Induction of tissue factor on monocytes by adhesion to endothelial cells

Activated monocytes express tissue factor (TF), a protein that is important in the pathogenesis of thrombotic disorders. We sought to characterize an adhesion-dependent pathway for monocyte activation. In this study, we showed that adhesion of monocytes to cytokine-activated endothelial cells (EC) increased (approximately 5- to 10-fold) monocyte procoagulant activity (PCA). The PCA was attributed to TF because it was dependent on the coagulation factors VII and X, but not VIII, and was completely blocked by an anti-TF mAb. Direct cell-cell contact between monocytes and EC was required. The induction of TF was rapid, peaked at 30 min, and persisted for 4 h. Northern analysis revealed a rapid (approximately 30 min) increase in TF mRNA following adhesion, distinct from that induced by LPS (approximately 2-4 h). Four-hour TNF-treated EC supported TF expression, but 0.5- and 24-h TNF-treated EC had no effect. An anti-E-selectin mAb (H18/7) exerted partial inhibition, whereas anti-VCAM-1, ICAM-1, and CD11/CD18 mAbs had no inhibition. Synthetic Lewis X (Le(x)) oligosaccharide partially blocked TF induction, whereas sialyl-Le(x) (sLex) oligosaccharide had no effect. Cross-linking Le(x) on monocytes, but not sLex, significantly increased (approximately 10-fold) the TF expression. Le(x) cross-linking induced TF in 30 min and lasted for 4 h. All seventeen anti-Le(x) mAbs induced significant amount of TF generation, and epitope mapping revealed a single binding epitope on Le(x). These findings indicate that adhesion of monocytes to activated EC induces TF generation, and also suggest that Le(x) may represent an important signaling molecule on monocytes.

Induction of tissue factor on monocytes by adhesion to endothelial cells

Activated monocytes express tissue factor (TF), a protein that is important in the pathogenesis of thrombotic disorders. We sought to characterize an adhesion-dependent pathway for monocyte activation. In this study, we showed that adhesion of monocytes to cytokine-activated endothelial cells (EC) increased (approximately 5- to 10-fold) monocyte procoagulant activity (PCA). The PCA was attributed to TF because it was dependent on the coagulation factors VII and X, but not VIII, and was completely blocked by an anti-TF mAb. Direct cell-cell contact between monocytes and EC was required. The induction of TF was rapid, peaked at 30 min, and persisted for 4 h. Northern analysis revealed a rapid (approximately 30 min) increase in TF mRNA following adhesion, distinct from that induced by LPS (approximately 2-4 h). Four-hour TNF-treated EC supported TF expression, but 0.5- and 24-h TNF-treated EC had no effect. An anti-E-selectin mAb (H18/7) exerted partial inhibition, whereas anti-VCAM-1, ICAM-1, and CD11/CD18 mAbs had no inhibition. Synthetic Lewis X (Le(x)) oligosaccharide partially blocked TF induction, whereas sialyl-Le(x) (sLex) oligosaccharide had no effect. Cross-linking Le(x) on monocytes, but not sLex, significantly increased (approximately 10-fold) the TF expression. Le(x) cross-linking induced TF in 30 min and lasted for 4 h. All seventeen anti-Le(x) mAbs induced significant amount of TF generation, and epitope mapping revealed a single binding epitope on Le(x). These findings indicate that adhesion of monocytes to activated EC induces TF generation, and also suggest that Le(x) may represent an important signaling molecule on monocytes.

[Constituents of lignanoids in Siphonostegia chinensis Benth]

A trace monomeric compound was isolated from the aerial part of Siphonostegia chinensis, and determined by X-ray diffraction as a lignanoid compound named syringaresinol. It is obtained from this plant as well as from Scrophulariaceae for the first time.

Describing the spread of biological populations using stochastic compartmental models with births

This paper derives new models for describing the spread of biological populations in space and time from classical birth-death-migration processes. The spatial aspect is incorporated using compartmental analysis and is developed for two spatial areas (or compartments). The exact bivariate distributions for such processes are intractable; hence approximating distributions are constructed by matching cumulants. A basic Markovian model with exponential waiting times between births is investigated first. The individual effects of swarming, multiple births, and Erlang distributed waiting times, all of which enhance the biological realism, are investigated. A full model which includes all of these effects is then studied. The models are illustrated with observed data on the spread of the Africanized honey bee in French Guiana. A full model with swarming, with an average of 2.64 colonies per swarming episode, and with waiting times following an Erlang distribution with shape parameter 5 is found to provide the best description of the observed data. The methodology is very general and should have broad application for other biological population models involving dispersal and growth.

Flexible docking of peptides to class I major-histocompatibility-complex receptors

We present a new method for docking flexible peptides to class I Major-Histocompatibility-Complex (MHC) receptors. Docking is performed in two steps: (a) The charged terminal peptide residues are located by randomly distributing multiple copies of each in volumes of approximately 150 A at either end of the binding groove, and then minimizing the system energy using a modified multiple-copy search algorithm. This is followed by (b) construction of the intervening chain using the multiple-copy bond-scaling-relaxation loop closure algorithm. In both steps, the copies tend to cluster and the size of the resulting clusters is proportional to the basin of attraction of the corresponding energy well. We show that native MHC-bound peptides have broad minima and, consequently, that misfolded, low-energy peptide conformations can be eliminated by restricting consideration to groups of peptides which cluster into broad minima. The accuracy of the method is assessed by comparing the predictions with crystallographic data for three different MHC peptide systems, at various degrees of stringency: (a) the extent to which we can determine side chain function (anchor vs. T-cell epitopes); (b) the extent to which we can determine the peptide-receptor orientation; and (c) the accuracy with which we can predict atomic coordinates. We find the method correct on (a) for 19 of the 22 non-Gly positions; the failures appearing to be a consequence of omitting solvation. Predictions related to (b) are also very encouraging, with the overall orientation of the predicted peptides being very similar to the crystal conformation, when measured by the hydrogen bonding pattern between the two. The degree of success in predicting atomic coordinates varied considerably, however, from 1.4 A for the HLA-A2 peptide to 2.7 A for the Kb peptide. The inaccuracy of the latter appears to reflect an incomplete target function, most likely the ommission of solvation. The calculations thus define the current limits of accuracy in docking flexible peptides to Class I receptors and identify the methodological improvements that must be made for the next advance in accuracy.

Quantitative reverse transcription polymerase chain reaction shows that ethanol enhances interleukin-6 mRNA expression in cultured mesangial cells

IgA nephropathy, a form of mesangial glomerulonephritis, is associated with chronic ethanol ingestion in humans and in a rat model. We investigated the hypothesis that ethanol has a direct effect on a mesangial cell cytokine, interleukin-6 (IL-6). We measured IL-6 mRNA in cultured mesangial cells using a novel method, quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR). Primers were used to amplify a 346-bp segment. To quantify the results, we generated an internal standard using site-directed mutagenesis which resulted in a restriction site for EcoRI, absent in target IL-6 cDNA. In the presence of the same primers, the mutated internal standard (exogenous template) amplifies with equal efficiency as the target IL-6 cDNA. Q-RT-PCR, using 250 ng of total RNA, showed that after ethanol incubation, IL-6 mRNA was 65 (+/-30) attomol, a 1.5-fold increase from 44 (+/-28) attomol in control cells. This study shows that in vitro, ethanol enhances IL-6 mRNA expression in rat mesangial cells.

On the exact hazard and survival functions of the MVK stochastic carcinogenesis model

The MVK two-stage carcinogenesis model is one of the most widely accepted mechanistic models in carcinogenesis modeling. However, due to a perceived difficulty in obtaining analytic solutions for the hazard and survival functions, approximations and numerical methods have been used to calculate these two fundamental quantities. This paper focuses on a special case of the homogeneous MVK model where the number of normal cells is constant. The probability generating function (pgf) for the number of tumor cells is derived, and the exact analytic solutions to the hazard and survival functions are obtained from the pgf.

A new staging system for nasopharyngeal carcinoma in China

PURPOSE

An accurate and rational nasopharyngeal carcinoma (NPC) stage based on images is proposed.

METHODS AND MATERIALS

Four hundred and twenty-one cases of NPC, treated in the Cancer Hospital, Sun Yat-sen University of Medical Sciences (SUMS), with computed tomography scanning before initial radiotherapy, are analyzed. Important prognostic factors that form the basis of the new staging system are screened out by means of Cox model and clinical experiences. Survival curves of various kinds of T and N stages are compared by computer simulation. A new staging system is proposed by studying the traditional staging systems such as the AJC, UICC, Ho's and Changsha systems.

RESULTS

According to the new staging criteria, the 5-year survival rates for Stages I-IV are 89.7%, 75.9%, 51.3%, and 22.2%, respectively.

CONCLUSION

This new clinical staging for NPC based on a large amount of cases multivariate analysis is satisfactory and widely used in China.

Multiple copy sampling: rigid versus flexible protein

Effects of protein flexibility on multiple copy conformational sampling were systematically evaluated by studying the side-chain placement of Phe-14 in protein Zif268. The multiple copy sampling is shown to be significantly more efficient when a flexible but harmonically constrained protein is used instead of a rigid protein. A range of constraint force from 1 to 25 kcal/mol.A per atom is determined to be sufficient to prevent the protein from distortion while allowing the protein to fluctuate for enhanced sampling. The protein fluctuations are essential in smoothing the effective energy surface as shown by the opening-closing of a protein hydrophobic pocket during a multiple copy energy minimization, a phenomenon that has been previously observed only in molecular dynamics. These results provide a practical guidance for applying the multiple copy techniques to molecular modeling and computer-aided drug design.

GLUT-1 and GLUT-2 mRNA, protein, and glucose transporter activity in cultured fetal and adult hepatocytes

To understand glycogenesis in the fetal hepatocyte, we examined glucose transport in cultured fetal and adult male rat hepatocytes. GLUT-1 mRNA was detected in fetal hepatocytes at isolation but in adult hepatocytes only after culture. GLUT-1 mRNA was more abundant in fetal than in adult hepatocytes (P < 0.005). GLUT-1 protein paralleled its message. GLUT-2 mRNA was more abundant in adult than in fetal hepatocytes (P < 0.05), and abundance did not change during culture, but GLUT-2 protein was discordantly regulated. There was more GLUT-2 protein in fetal hepatocytes at 45 h (P < 0.025). An Eadie-Hofstee plot of 3-O-methylglucose transport appeared to have two linear components. One component was presumed to be GLUT-1 [variable Michaelis constant (Km) approximating 6-8 mM, maximal uptake rate (Vmax) for fetal vs. adult hepatocytes 106 vs. 35 nmol.min-1.mg protein-1], and a second was presumed to be GLUT-2 (Km of 23 mM, Vmax for fetal vs. adult hepatocytes 198 vs. 92 nmol.min-1.mg protein-1). Early phosphorylation of 2-deoxyglucose was greater in fetal than in adult hepatocytes, but transport was always greater than phosphorylation. Increased expression of both GLUT-1 and GLUT-2 by fetal hepatocytes permits greater glucose uptake and positions the fetal rat hepatocyte for efficient glycogenesis at low plasma glucose concentration.

[Studies on the constituents of the roots of Acorus calamus L]

A new tricyclic sesquiterpene, named calamenone (1), and two known sesquiterpenes, calamendiol (2) and isocalamendiol (3), were isolated from the roots of Acorus calamus L. The structure of the new compound was elucidated on the basis of spectral and X-ray diffraction data.

Multiple copy sampling in protein loop modeling: computational efficiency and sensitivity to dihedral angle perturbations

Multiple copy sampling and the bond scaling-relaxation technique are combined to generate 3-dimensional conformations of protein loop segments. The computational efficiency and sensitivity to initial loop copy dispersion are analyzed. The multicopy loop modeling method requires approximately 20-50% of the computational time required by the single-copy method for the various protein segments tested. An analytical formula is proposed to estimate the computational gain prior to carrying out a multicopy simulation. When 7-residue loops within flexible proteins are modeled, each multicopy simulation can sample a set of loop conformations with initial dispersions up to +/- 15 degrees for backbone and +/- 30 degrees for side-chain rotatable dihedral angles. The dispersions are larger for shorter and smaller for longer and/or surface loops. The degree of convergence of loop copies during a simulation can be used to complement commonly used target functions (such as potential energy) for distinguishing between native and misfolded conformations. Furthermore, this convergence also reflects the conformational flexibility of the modeled protein segment. Application to simultaneously building all 6 hypervariable loops of an antibody is discussed.

[Anti-implantation action of nylestriol and its effect on endometrium in rabbits]

The anti-implantation action of nylestriol in rabbits was studied. Using the method of arresting mitosis by injection of colchicine, we detected the mitosis frequency of endometrial cells. The activities of carbonic anhydrase (CAH), A1P and PAS reaction were observed under light microscope combined with the histochemical method and microscopic autoexposure control device. The results were as follows: 1. Giving nylestriol orally to rabbits on day 1 of pregnancy produced an obvious anti-implantation effect; 2. The number of mitosis cells in glandular epithelium and stroma of the endometrium in the treatment group was less than that in the control group (P < 0.05); and 3. Compared with the control group, the activities of CAH and A1P, and glycogen content in the endometrium decreased significantly in the treatment group (P < 0.05). The result suggests that nylestriol may prevent the implantation of blastocyst by disturbing decidulization of the endometrium.

[Epidemiology of adenovirus pneumonia in Beijing, 1976-1990]

From 1976 to 1990 for 15 consecutive epidemic years, virological examinations were carried out on 2,757 hospitalized infants and children infected with pneumonia. Ninety-nine strains of types 3 and 7 adenovirus (Ad3,Ad7) isolated from 50s to 90s were analyzed with 12 DNA restriction endonucleases. Results showed the epidemiologic characteristics of adenovirus (Adv) pneumonia in Beijing. Epidemic occurred yearly, but there was no severe outbreak of Adv pneumonia as in 1958. Ad3 and Ad7 were the main etiologic agents of Adv pneumonia. Ad7 was dominant in 1976-1980; while Ad3 was more prevalent in 1981-1990. DNA restriction endonuclease analysis revealed six genome types of Ad7 and three genotypes of Ad3. 7a1, 7a4, 7b and 7g occurred in 1958, 1965, but disappeared between 1980-1990; 3a2 was first detected in 1962. From 1980 to 1990, 7d and 3a2 were the dominant genome types. Among the Ad7 strains only one strain of 7d1 was identified; all others were 7d. 3a4 and 3a6 first appeared in 1984 and 1986, respectively. The changes of epidemic patterns seemed correlated with the variations of genome types.

Computing the structure of bound peptides. Application to antigen recognition by class I major histocompatibility complex receptors

The ability to accurately compute the atomic positions of substrate-bound ligands is central to understanding biological recognition. Although substantial progress has been made in docking small, relatively rigid ligands, the problem of docking flexible peptides remains open. In this communication we present a new method that allows configurational flexibility of peptides, and apply it to predict the conformation of peptides bound to two class-I major histocompatibility complex receptors: human HLA-A2, and murine H-2Kb. Using only the approximate locations of the amino and carboxyl-terminal residues of the bound peptide, our calculations yield structures with backbone conformations that are similar to structures reported crystallographically.