Effects of Lactobacillus GG on genes expression pattern in small bowel mucosa

BACKGROUND AND AIMS

Probiotics have been used for cure and prevention of several clinical conditions. However, further insights into the mechanism of action are needed to understand the rationale of their use. The aim of this study was to investigate the influence of Lactobacillus GG on the genetic expression patterns in the small bowel mucosa.

METHODS

Six male patients (38+/-5 years) with endoscopically proven oesophagitis were enrolled. All patients were treated for 1 month with esomeprazole and randomised to receive Lactobacillus GG or placebo. After 1 month of treatment, upper endoscopy was repeated. Biopsies of the duodenal mucosa were taken prior to and after the treatment, and the genes expression patterns were assessed using GeneChip Human U133A array. Genes with significant expression changes were selected and analysed to identify specific cellular pathways modified by Lactobacillus GG. To support the array data, 10 target genes were studied using Syber-Green PCR.

RESULTS

Microarray analysis showed that Lactobacillus GG administration determined the up- and down-regulation of 334 and 92 genes, respectively. Real-time PCR confirmed the reliability of the analysis. Lactobacillus GG mainly affected the expression of genes involved in immune response and inflammation (TGF-beta and TNF family members, cytokines, nitric oxide synthase 1, defensin alpha 1), apoptosis, cell growth and cell differentiation (cyclins and caspases, oncogenes), cell-cell signalling (ICAMs and integrins), cell adhesion (cadherins), signal transcription and transduction.

CONCLUSIONS

These data indicate that administration of Lactobacillus GG is associated with a complex genetic response of the duodenal mucosa, reflected by the up- and down-regulation of several genes involved in specific cellular pathways.

Distribution of PCBs, HCHs and DDTs, and their ecotoxicological implications in Bay of Bengal, India

Analyses of environmentally persistent pollutants like polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, and dichlorodiphenyltrichloroethane (DDT) and its metabolites in seawater and sediment samples collected from six locations along the east coast of India were carried out using High-Resolution Gas Chromatograph with High-Resolution Mass Spectrometer (HRGC-HRMS). Sediment and water from Chennai harbour and Cuddalore fishing harbour contained higher concentration of all the compounds. The highest concentration (6570 pg/g dry weight) of total PCB was found in sediment from Chennai harbour followed by sediments sampled in Chennai (opposite to Cooum River mouth) (505 pg/g), Cuddalore fishing harbour (335 pg/g) and Mandapam (251 pg/g). Concentrations in other locations were two orders of magnitude lower than Chennai harbour. A distinct PCB distribution pattern in sediment was observed between harbours and other locations. Greater concentrations of tetra-, penta- and hexachlorobiphenyls were observed in sediments of harbours and opposite to Cooum river mouth, but in other locations lower chlorinated biphenyls (di, tri and tetra-) were more. In seawater, HCH concentration was greater than DDT, but it was quite opposite in sediments. Elevated levels of DDT in sediment were observed only at highly populated urban locations, reflecting the local usage and input of this pesticide. Based on sediment/water quality criteria/guidelines, some coastal locations of the Bay of Bengal could be designated as being polluted by DDTs and gamma-HCH (lindane), but not by PCBs. This investigation reveals the declining trend on the environmental burden of persistent pesticides in Indian marine environment. Data on the organochlorine concentrations found in this survey can be used as reference levels for future POPs monitoring programme.

A novel STK11 germline mutation in two siblings with Peutz-Jeghers syndrome complicated by primary gastric cancer

Patients with Peutz-Jeghers syndrome (PJS) are known to be at risk of gastric cancer (GC), and the STK11 gene is a susceptibility gene for PJS. However, as no cases of PJS with GC in which a STK11 germline mutation has been identified have ever been reported and other susceptibility genes have also been suggested to be involved in PJS, the relation between STK11 germline mutations and GC in PJS is still unknown. In this study, we used sequencing analysis to investigate the STK11, CDH1, and TP53 loci for a germline mutation in two siblings with PJS with primary GC. A novel type of the STK11 germline mutation, c.890delG, encoding a truncated protein (p.Arg297fsX38) was identified, but no germline mutations of the CDH1 and TP53 genes were detected. No inactivation of the wild-type allele by somatic mutation or chromosomal deletion or hypermethylation at the 5'-CpG site of STK11 was detected in the GC. This is the first report of a STK11 germline mutation in a PJS patient with GC and should contribute to establishing correlations between the STK11 germline mutations and GC in PJS patients.

Microencapsulation and culture in vitro of rat pinealocytes

BACKGROUND

Melatonin is a powerful anti-aging reagent for scavenging free radicals. However, the effect of exogenous melatonin on age-dependent diseases is uncertain. Immune rejection has limited xenotransplantation or allotransplantation of the pineal gland. The aim of this study was to assess cell viability and the function of rat pinealocytes encapsulated in APA capsules and offer experimental suggestions for pineal microencapsulation grafting to resist aging.

METHODS

The pineal glands of neonatal rats were removed. Pinealocytes were isolated and encapsulated in APA microencapsulation and cultured. Morphological appearance of the microencapsulation was observed. Trypan blue staining and 5-HT immunocytochemical assay were used to detect cell viability and identify pinealocytes. The expression of AA-NAT mRNA was confirmed by RT-PCR. Melatonin release was measured and compared by HPLC.

RESULTS

Both control and encapsulated pinealocyte cultures survived well. The majority of the encapsulated pinealocytes as well as unencapsulated cells remained 5-HT positive. No significant difference in melatonin secretion and the expression level of AA-NAT mRNA between encapsulated and unencapsulated pinealocytes was found.

CONCLUSIONS

Pinealocytes survive and remain functionally competent in vitro at least 2 weeks after microencapsulation.

[First discovery of Taenia saginata asiatica infection in Yunnan province]

AIM

To investigate the aetiology, species and epidemiological factors of Taenia infection in a pilot area of Lanping County, Yunnan Province.

METHODS

Two patients with taeniasis were treated with antiscolex capsule and praziquantel, respectively. Five local weaning pigs free from tapeworm infection were fed with gravid proglottids obtained from the patients. After 2-3 months, the pigs were necropsied to examine cysticerci. In addition, one pig naturally infected with Taenia was treated as well.

RESULTS

Based on morphological characteristics of the scolex and gravid proglottid of four tapeworms obtained from the patients, the worms were similar to T. saginata. 23 cysticerci recovered from two experimentally infected pigs were found in the livers, omentum majus and mesenterium, and 3 cysticerci were found in the liver and omentum majus in a naturally infected pig as well. The protoscolex of mature Cysticercus had two rows of rudimentary hooklets, one rostellum and four acetabula resembling to C. cellulosae. According to morphological characteristics and the location of cysticerci, the tapeworm was identified as Taenia saginata asiatia.

CONCLUSION

T. saginata asiatica infection was first reported in Yunnan Province.

HLA-DPB1 allelic frequency of the Pumi ethnic group in south-west China and evolutionary relationship of Pumi with other populations

A sequencing-based typing of the HLA-DPB1 gene was carried out in 51 unrelated healthy individuals from the Yunnan Pumi ethnic minority. A total of 18 DPB1 alleles, in which DPB1*0501 (52.0%) and DPB1*0402 (15.7%) greatly predominated, were found, of which alleles DPB1*20011, 2201, 3601, 3701, 3801, 4901, 5001 and 8001 were recorded for the first time in the Chinese population. This may be because the typing methods used in previous genotyping of Chinese populations were of lower sensitivity than that used in our study. A dendrogram constructed by the maximum likelihood method showed that the Pumi ethnic minority belongs to the Asian/Australasian cluster and has the closest relationship to Trobriander, implying an unusual relationship between Australasian and South China populations. However, the Yi ethnic minority, which also comes from the ancient Qiang, did not show a very close relationship with the Pumi. This is probably because the Pumi were historically assimilated by local south-west China populations.

Screening of gene expression profiles in gastric epithelial cells induced by Helicobacter pylori using microarray analysis

BACKGROUND

H. pylori infection is a major risk factor in gastric cancer development. The availability of cDNA microarrays creates the unprecedented opportunity to examine simultaneously dynamic changes of multiple pathways affected by H. pylori infection.

AIM

In this study we examined broad patterns of gene expression induced by H. pylori in the gastric cancer cell line 1739-CRL AGS cells in culture using the U95A microarray.

METHODS

H. pylori were cocultured with AGS cells for 4, 12, 24 and 48 h. Total RNA was extracted and after labelling was used for detection of genes represented in the human U95A microarray set. Data analyses were performed using GeneChip and CLUSFAVOR software.

RESULTS

Nearly 6000 genes present in the array were expressed by AGS cells. We report approximately 200 genes that showed the most marked changes. Our studies confirm the up-regulation of c-jun, jun-B, c-fos and cyclin D1 by H. pylori. We report for the first time the induction of the serine threonine kinase pim-1 and ATF3 by H. pylori infection of AGS cells.

CONCLUSIONS

In this microarray analysis of gene expression induced by H. pylori in gastric epithelial cells, we identified a large number of unsuspected genes affected by H. pylori. Further, we show that unsupervised hierarchical cluster analysis can provide useful insight into the possible contribution of genes in specific pathways, based on their profile of expression.

Determination of butyl-, phenyl-, octyl- and tributylmonomethyltin compounds in a marine environment (Bay of Bengal, India) using gas chromatography-inductively coupled plasma mass spectrometry

Organotin compounds (butyl-, phenyl-, octyl- and tributylmonomethyltin) and inorganic tin were quantified in sea-water and sediments from two harbours and several locations on the southeast coast of India using highly sensitive and selective gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS), adopting new extraction and analytical techniques with extremely low detection limits (water, 0.019-0.85 pg l(-1); sediment, 0.23-0.48 ng g(-1)). The concentrations of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in sea-water from Tuticorin harbour varied from 0.64 to 4.97, 3.0 to 26.8 and 0.3 to 30.4 ng Sn l(-1), respectively. MBT, DBT and TBT in sediments from harbour areas ranged from 1.6 to 393, 1.3 to 394 and ND (not detected) to 1280 ng Sn g(-1) (dry weight), respectively. Natural methylation in both harbours was established by quantifying tributylmonomethyltin (TBMMT) residues (sea-water, ND-0.19 ng Sn l(-1); sediment, ND-765 ng Sn g(-1) dry weight). In sea-water, octyltins were also determined as monooctyltin (MOT) > dioctyltin (DOT) > trioctyltin (TOT). Butyltin contamination in commercial harbours is evident, but other coastal waters are not contaminated with organotin residues. The high concentration of inorganic tin in estuarine sediment indicates an elevated rate of debutylation in the estuarine environment. Both methylation and debutylation of TBT in Chennai harbour were greater than in Tuticorin harbour. A significant correlation (r2 = 0.75) between total butyltin and organic carbon contents in sediment was found. To our knowledge, this is the first report on the distribution of butyltins and methylated butyltin in sea-water and sediment and octyltins in sea-water in the Indian marine environment.

Intestinal mast cell progenitors require CD49dbeta7 (alpha4beta7 integrin) for tissue-specific homing

Mast cells (MCs) are centrally important in allergic inflammation of the airways, as well as in the intestinal immune response to helminth infection. A single lineage of bone marrow (BM)-derived progenitors emigrates from the circulation and matures into phenotypically distinct MCs in different tissues. Because the mechanisms of MC progenitor (MCp) homing to peripheral tissues have not been evaluated, we used limiting dilution analysis to measure the concentration of MCp in various tissues of mice deficient for candidate homing molecules. MCp were almost completely absent in the small intestine but were present in the lung, spleen, BM, and large intestine of beta7 integrin-deficient mice (on the C57BL/6 background), indicating that a beta7 integrin is critical for homing of these cells to the small intestine. MCp concentrations were not altered in the tissues of mice deficient in the alphaE integrin (CD103), the beta2 integrin (CD18), or the recombination activating gene (RAG)-2 gene either alone or in combination with the interleukin (IL)-receptor common gamma chain. Therefore, it is the alpha4beta7 integrin and not the alphaEbeta7 integrin that is critical, and lymphocytes and natural killer cells play no role in directing MCp migration under basal conditions. When MCp in BALB/c mice were eliminated with sublethal doses of gamma-radiation and then reconstituted with syngeneic BM, the administration of anti-alpha4beta7 integrin, anti-alpha4 integrin, anti-beta7 integrin, or anti-MAdCAM-1 monoclonal antibodies (mAbs) blocked the recovery of MCp in the small intestine. The blocking mAbs could be administered as late as 4 d after BM reconstitution with optimal inhibition, implying that the MCp must arise first in the BM, circulate in the vasculature, and then translocate into the intestine. Inasmuch as MCp are preserved in the lungs of beta7 integrin-deficient and anti-alpha4beta7 integrin-treated mice but not in the small intestine, alpha4beta7 integrin is critical for tissue specific extravasation for localization of MCp in the small intestine, but not the lungs.

Engineering a homo-ethanol pathway in Escherichia coli: increased glycolytic flux and levels of expression of glycolytic genes during xylose fermentation

Replacement of the native fermentation pathway in Escherichia coli B with a homo-ethanol pathway from Zymomonas mobilis (pdc and adhB genes) resulted in a 30 to 50% increase in growth rate and glycolytic flux during the anaerobic fermentation of xylose. Gene array analysis was used as a tool to investigate differences in expression levels for the 30 genes involved in xylose catabolism in the parent (strain B) and the engineered strain (KO11). Of the 4,290 total open reading frames, only 8% were expressed at a significantly higher level in KO11 (P < 0.05). In contrast, over half of the 30 genes involved in the catabolism of xylose to pyruvate were expressed at 1.5-fold- to 8-fold-higher levels in KO11. For 14 of the 30 genes, higher expression was statistically significant at the 95% confidence level (xylAB, xylE, xylFG, xylR, rpiA, rpiB, pfkA, fbaA, tpiA, gapA, pgk, and pykA) during active fermentation (6, 12, and 24 h). Values at single time points for only four of these genes (eno, fbaA, fbaB, and talA) were higher in strain B than in KO11. The relationship between changes in mRNA (cDNA) levels and changes in specific activities was verified for two genes (xylA and xylB) with good agreement. In KO11, expression levels and activities were threefold higher than in strain B for xylose isomerase (xylA) and twofold higher for xylulokinase (xylB). Increased expression of genes involved in xylose catabolism is proposed as the basis for the increase in growth rate and glycolytic flux in ethanologenic KO11.

[Expression and significance of TGF-beta 1 in nasal polyps]

OBJECTIVE

To study the expression and significance of transforming growth factor-beta 1(TGF-beta 1) in nasal polyps.

METHOD

Expression of TGF-beta 1 in nasal polyps from 34 patients and middle turbinates from 30 patients with deviation of nasal septum were prospectively studied with immunohistochemistry. Each tissue section was observed under optical microscope.

RESULT

1. The TGF-beta 1 positivity in extracellular matrix and in cells in the stroma was significantly higher in nasal polyps than in middle turbinates (P < 0.01). 2. The distribution and shape of TGF-beta 1 expressing cells in nasal polyps was similar to that of eosinophil, their positivities were significantly correlative (P < 0.05). 3. The positivity of TGF-beta 1 did not correlate with clinical type of nasal polyps (P > 0.05), eosinophil infiltration correlated significantly with clinical type of nasal polyps(P < 0.05).

CONCLUSION

1. The TGF-beta 1 may contribute to some of the pathologic changes observed in nasal polyps, such as thickening of the epithelial basement membrane and stromal fibrosis. 2. Eosinophils in nasal polyps represent a major source of TGF-beta 1. 3. Eosinophils infiltration may play a prominent role in the development and recurrence of nasal polyps.

[Analysis of HLA-DQB1 polymorphism by PCR-SSO in Yichu of Yunnan Province]

HLA-DQB1 genes from 76 individuals of Yichu ethnic group in Yunnan Province were investigated, using PCR-SSO genotyping method. Of the 38 DQB1 alleles detected, DQB1 * 0301 (gene frequency: 36.18%-36.84%) was the most common gene. The frequencies of DQB1 * 0502(10.53%-11.18%), DQB1 * 0401 (9.21%), DQB1 * 0302(8.55%-9.21%), DQB1 * 0601(7.89%), DQB1 * 05031(6.58%), and DQB1 * 03032(5.92%-6.58%) are more than 5%. While DQB1 * 0504, DQB1 * 0604, DQB1 * 06052, DQB1 * 0606, DQB1 * 0607, DQB1 * 0608, DQB1 * 06112, DQB1 * 0613, DQB1 * 0615, DQB1 * 0203, DQB1 * 0305, DQB1 * 0306, DQB1 * 0307, and DQB1 * 0308 were not observed. Comparison of HLA-DQB1 allele frequencies of Yichu with those of 13 other Chinese ethnic groups showed some significant differences, suggesting Yichu is unique in the distribution of HLA alleles.

Cloning and expression of the chick p63 gene

We have isolated a chick cDNA for p63, a member of the p53 transcription factor family. This cDNA encodes a protein of 582 amino acids for an alpha isoform in the C-terminal region, while lacking the N-terminal transactivation domain. The chick p63 gene is first expressed in the prospective cutaneous ectoderm at stage 6 and later in the developing epithelia. The p63 expression is intense in specialized epithelial structures, such as apical ectodermal ridge of the limb bud, epithelia of branchial arches and feather buds. Furthermore, we have found that the transcripts are detected in the interdigital epithelium, intersomite epithelium, and epaxial dermamyotome.

A comparison of polymorphism in the 3'-untranslated region of the prothrombin gene between Chinese and Caucasians in Australia

The 20210G-->A mutation in the 3'-untranslated (UT) region of the prothrombin gene is extremely rare or absent in the Chinese population (0 in 449 subjects, 140 with a history of thromboembolism). This is in contrast to the results from 302 Caucasians from Australia in our study (4.6% in 153 patients with a thromboembolic history and 1.3% in 149 patients with no history). This rarity implies that the variant of the prothrombin gene is probably not the main cause of venous thromboembolism in the Chinese population. Even among Caucasians this mutation accounts for only a minor percentage of all patients with thromboembolism. The relatively low incidence of venous thromboembolism in the Chinese population compared with Caucasians is probably as a result of the low prevalence of factor V Leiden or other environmental or genetic factors.

A quantitative extraction method for the determination of trace amounts of both butyl- and phenyltin compounds in sediments by gas chromatography-inductively coupled plasma mass spectrometry

A simple and reliable extraction method was developed for quantitative determination of both butyl- and phenyltin compounds in sediments by capillary gas chromatography combined with inductively coupled plasma mass spectrometry (GC-ICP-MS). Both types of organotin compounds were extracted quantitatively from sediment by mechanical shaking into tropolone-toluene and HCl-methanol. After phase separation and pH adjustment, these organotins were ethylated with sodium tetraethylborate. The method was evaluated by analyzing PACS-2 and NIES No. 12 sediment certified reference materials. The dibutyltin (DBT; 1.14 +/- 0.02 micrograms g-1) and tributyltin (TBT; 1.01 +/- 0.04 micrograms g-1) values observed in PACS-2 sediment closely matched the certified values (DBT, 1.09 +/- 0.15; TBT, 0.98 +/- 0.13 microgram g-1 as tin). The monobutyltin (MBT) value was higher (0.62 +/- 0.02 microgram g-1) by more than two fold over the reference value (0.3 microgram g-1 as tin). The concentrations of TBT (0.18 +/- 0.04 microgram g-1) and triphenyltin (TPhT; 0.0099 +/- 0.002 microgram g-1) in the NIES No. 12 sediment were also in good agreement with the certified and reference values of TBT (0.19 +/- 0.03 microgram g-1 as compound) and TPhT (0.008 microgram g-1 as compound), respectively. Recoveries of TBT, tripentyltin (TPeT) and TPhT from spiked sediments were satisfactory (TBT, 102 +/- 3.4%; TPrT, 96 +/- 3.4%; TPhT, 99 +/- 8.5%). The detection limits as tin were in the range 0.23-0.48 ng g-1 for a 0.5 g sample size. It is also noteworthy that clean-up of the extract is not necessary because of the superior selectivity of ICP-MS detection. The present method was successfully applied to marine sediment samples.

[Effect of foliar leaching on growth and mineral nutrition of maize under NaCl stress]

The impact of foliar leaching on growth and mineral nutrition maize under NaCl stress was investigated. The results showed that there was no difference in biomass between leaching and control treatments under low NaCl stress (0 and 50 mmol.L-1), but under high NaCl stress (100 and 200 mmol.L-1), the biomass of leaching treatment was higher, with a better at pH 3.5 than at pH 7.0. The shoot K+ content in leaching treatments was higher than that of control under no NaCl stress, but lower under 200 mmol.L-1 NaCl stress. Shoot Na+ content of leaching treatments was lower than that of control under high NaCl stress, and shoot Ca2+ and Mg2+ contents of leaching treatments were higher under no NaCl stress. Root K+, Na+, Ca2+ and Mg2+ content and relative water content of leaching treatments had no significant changes, compared with those of control. It was suggested that foliar leaching could alleviate harmful degree of maize under serious salt stress, which was related with the decrease of shoot Na+ content by foliar leaching.

[Effect of ginsenosides on proliferation and differentiation of human CD34+ hematopoietic stem/progenitor cells]

OBJECTIVE

To investigate the effect of ginsenosides (GS) on proliferation and differentiation of human CD34+ stem/progenitor cells.

METHODS

CD34+ hematopoietic progenitor cells were isolated from umbilical cord blood by using the immune beads sorting system. The cells were exposed to GS of different concentrations in both liquid culture and semi-solid culture, and the elevation rate on proliferation of CD34+ stem/progenitor cells and colony formation were estimated. The cells were marked with monoclonal antibody and the marker was examined by flow cytometry after incubated with GS for 14 days.

RESULTS

GS (5-50 micrograms/ml) could raise the colony production rate of BFU-E, CFU-E, CFU-GM, CFU-GEMM by (87.6 +/- 2.6)%, (63.3 +/- 2.8)%, (58.0 +/- 3.1)% and (96.3 +/- 5.5)% respectively (all P < 0.01), and the best effect in improving cell proliferation of CD34+ cells in vitro was obtained when the concentration of GS was 25 micrograms/ml. After incubation with GS for 14 days, number of CD33+ cells was increased by GS in a dose-dependent manner with a peak increasing rate at 200 micrograms/ml. In the presence of GS 50 micrograms/ml, CD15+ cells were reaching the peak. Number of CD71+ and G-A+ cells increased only when the concentration of GS was 25 micrograms/ml.

CONCLUSION

GS could not only promote the proliferation but also induce the differentiation of CD34+ hematopoietic stem/progenitor cells, GS may play the role by cooperating with hematopoietic growth factor, and by its growth factor-like function in the regulation of hematopoiesis.

Examining methods for calculations of binding free energies: LRA, LIE, PDLD-LRA, and PDLD/S-LRA calculations of ligands binding to an HIV protease

Several strategies for evaluation of the protein-ligand binding free energies are examined. Particular emphasis is placed on the Linear Response Approximation (LRA) (Lee et. al., Prot Eng 1992;5:215-228) and the Linear Interaction Energy (LIE) method (Aqvist et. al., Prot Eng 1994;7:385-391). The performance of the Protein Dipoles Langevin Dipoles (PDLD) method and its semi-microscopic version (the PDLD/S method) is also considered. The examination is done by using these methods in the evaluating of the binding free energies of neutral C2-symmetric cyclic urea-based molecules to Human Immunodeficiency Virus (HIV) protease. Our starting point is the introduction of a thermodynamic cycle that decomposes the total binding free energy to electrostatic and non-electrostatic contributions. This cycle is closely related to the cycle introduced in our original LRA study (Lee et. al., Prot Eng 1992;5:215-228). The electrostatic contribution is evaluated within the LRA formulation by averaging the protein-ligand (and/or solvent-ligand) electrostatic energy over trajectories that are propagated on the potentials of both the polar and non-polar (where all residual charges are set to zero) states of the ligand. This average involves a scaling factor of 0.5 for the contributions from each state and this factor is being used in both the LRA and LIE methods. The difference is, however, that the LIE method neglects the contribution from trajectories over the potential of the non-polar state. This approximation is entirely valid in studies of ligands in water but not necessarily in active sites of proteins. It is found in the present case that the contribution from the non-polar states to the protein-ligand binding energy is rather small. Nevertheless, it is clearly expected that this term is not negligible in cases where the protein provides preorganized environment to stabilize the residual charges of the ligand. This contribution can be particularly important in cases of charged ligands. The analysis of the non-electrostatic term is much more complex. It is concluded that within the LRA method one has to complete the relevant thermodynamic cycle by evaluating the binding free energy of the "non-polar" ligand, l;, where all the residual charges are set to zero. It is shown that the LIE term, which involves the scaling of the van der Waals interaction by a constant beta (usually in the order of 0.15 to 0.25), corresponds to this part of the cycle. In order to elucidate the nature of this non-electrostatic term and the origin of the scaling constant beta, it is important to evaluate explicitly the different contributions to the binding energy of the non-polar ligand, DeltaG(bind,l;). Since this cannot be done at present (for relatively large ligands) by rigorous free energy perturbation approaches, we evaluate DeltaG(bind,l;) by the PDLD approach, augmented by microscopic calculations of the change in configurational entropy upon binding. This evaluation takes into account the van der Waals, hydrophobic, water penetration and entropic contributions, which are the most important free energy contributions that make up the total DeltaG(bind,l;). The sum of these contributions is scaled by a factor straight theta and it is argued that obtaining a quantitative balance between these contributions should result in straight theta = 1. By doing so we should have a reliable estimate of the value of the LIE beta and a way to understand its origin. The present approach gives straight theta values between 0.5 and 0.73, depending on the approximation used. This is encouraging but still not satisfying. Nevertheless, one might be able to use our PDLD approach to estimate the change of the LIE straight theta between different protein active sites. It is pointed out that the LIE method is quite similar to our original approach where the electrostatic term was evaluated by the LRA method and the non-electrostatic term by the PDLD method (with its vdw, solvation,

[Relations of chemotherapy-induced tumor necrosis to plasma platin concentration and primary tumor temperature in patients with osteosarcoma in the lower extremities treated by hyperthermic isolation limb perfusion with cisplatin]

OBJECTIVES

To study the relations of chemotherapy-induced tumor necrosis to plasma concentration of platin and primary tumor temperature in hyperthermic isolation limb perfusion (HILP) with cisplatin, and to investigate the correlation between the tumor necrosis rate and the relapse-free survival (RFS).

METHODS

Fifteen patients with II B osteosarcoma in the lower extremities were treated with neoadjuvant chemotherapy. Among them, 10 were male and 5 female. The average age was 18 years (ranging from 13 to 29). Chemotherapy included a single bonus dose of HILP with cisplatin (CDDP, 15 mg/m(2)). The plasma concentration of platin and the tumor temperature in the affected limb were measured during the course of the HILP with CDDP. Limb salvage surgery was performed in 9 patients and amputation in 6. After surgery, serial sections of the excised tumor specimens were made to determine the tumor necrosis rate. All of the patients were followed up for more than 5 years.

RESULTS

The highest attained tumor temperature was between 41.4 degrees C - 43.0 degrees C (mean 42.3 degrees C +/- 0.46 degrees C), and the platin concentration ranged from 4.56 microg/mL to 14.66 microg/mL (mean 8.93 microg/mL +/- 3.16 microg/mL) during the course of HILP with CDDP. Thirteen patients with a necrosis rate of over 90% were well responded, and the remaining two with a necrosis rate 87.2% and 86.3% were poor responded. Eight patients remained tumor-free for 5 years. Primary tumor temperature and platin concentration were significantly related to the tumor necrosis rate (P = 0.001 and P < 0.001, respectively). No significant correlation was noted between the long-term survival rate and the three parameters in the regression analysis.

CONCLUSIONS

HILP with CDDP is useful in the treatment of primary osteosarcoma. Increased tumor necrosis ensure a successful surgical excision of tumor. HILP however is still limited to the patients who are not candidates for lime salvage surgery, because the same condition of high temperature and high concentration of platin are not applicable to distant metastasis.

Selective presynaptic propagation of long-term potentiation in defined neural networks

Induction of long-term potentiation (LTP) of the synaptic connection between two hippocampal glutamatergic neurons in a neural network formed in cell culture resulted in a specific pattern of potentiation at other connections within the network. We found that potentiation propagated from the site of induction retrogradely to glutamatergic or GABAergic synapses received by the dendrites of the presynaptic neuron and laterally to those made by its axonal collaterals onto other glutamatergic cells. In contrast, synapses made by the same presynaptic neuron onto GABAergic cells were not affected, and there was no postsynaptic lateral or forward propagation to other synapses received or made by the postsynaptic neuron. In addition, there was no secondary propagation to synapses not directly associated with the presynaptic neuron. Both induction and propagation of LTP required correlated spiking of the postsynaptic cell as well as the activation of the NMDA subtype of glutamate receptors. Such selective propagation suggests the existence of a long-range cytoplasmic signaling within the presynaptic neuron, leading to a specific pattern of coordinated potentiation along excitatory pathways in a neural network.

[Experimental study on selective thrombolytic activity of pro-urokinase]

OBJECTIVE

To evaluate the valve of pro-urokinase as a selective thrombolytic agent in microsurgery.

METHODS

The levators muscle model in rats was used to investigate the effect of pro-urokinase on dissolving ischemic thrombi and fibrinogenolytic activities in circulation by local infusion. The tissue microcirculation, pathologic appearance of rat lungs and muscles, and general fibrinogenolytic activities were observed.

RESULTS

The thrombolytic rate of pro-urokinase was 92.3% (P < 0.05), the positive rate of D-dime was 83.3%(P < 0.05). No significant change of alpha 2-PI was observed on general fibrinogenolytic activities(P > 0.05).

CONCLUSIONS

It is suggested that pro-urokinase can be used to dissolve the thrombi in microcirculation of free tissue transplantation without affect general fibrinogenolytic activities. It is safe to use pro-urokinase in free tissue transplantation.

Computer-aided 3-D reconstruction and measurement of the optic canal and intracanalicular structures

OBJECTIVE

To reconstruct the human optic canal and its inner structures, and to provide detailed knowledge of this region for optic nerve decompression for further understanding on the pathologic mechanisms of indirect optic nerve injury.

METHODS

Six optic canals and their inner structures were reconstructed using a computer-aided 3-dimensional reconstruction system. Quantitative measurement of the canal wall thickness, bony canal transverse area, optic nerve transverse area, dural sheath transverse area, subarachnoid space transverse area, and subarachnoid space volume were done by means of the computer morphometric analysis system. The detailed spatial relationship among intracanalicular structures were also carefully identified on the 3-D models.

RESULTS

The thinnest portion of the canal was the middle part of the medial wall (0.45 +/- 0.35 mm) and the narrowest space was in the middle part of the optic canal (the transverse area was 18.21 +/- 2.50 mm2). The volume of subarachnoid space which can be considered the compensatory space for distention incurred by the hemorrhage, optic nerve edema, or hematoma was 21.16 +/- 4.31 mm3. At the cranial opening, the middle part and orbital opening, its transverse area was 4.45 +/- 1.12 mm2, 2.68 +/- 1.32 mm2 and 1.23 +/- 0.83 mm2, respectively.

CONCLUSIONS

Since the compensatory space was limited, even a tiny amount of blood or swelling of the nerve may cause optic nerve compression. Because the narrowest space was in the middle part of the optic canal and the compensatory space for distention gradually decreases from cranial end to orbital end, the middle part and the anterior part of the optic canal and dural sheath are critical in optic nerve decompression.