[Etiologic study on the relationship between HBV, HCV and HCC]

A total of 110 HCC patients were sampled randomly in 20 townships of Qidong county (a higher incidence area of HCC in China) from Mar. to Sept. 1989. Each patient was paired with two healthy persons as control. The results showed that the prevalences of HBV and HCV in 110 patients were 85.45% and 17.27% respectively, and were significantly higher that in control (50.45% and 4.09%). Using Conditional Logistic Regression Model. we found that the main risk factors of HCC in Qidong were HBsAg and Pre-S2 for HBV and anti-HCV for HCV. The OR value were 10.22, 2.96 and 2.63, respectively. Drinking tea was the only protective factor (OR = 0.36). Among 110 HCC patients. 13.64% were positive for both HBV and HCV. The OR value was the highest (6.48). 88.18% patients were either HBV or HCV positive. The OR values were similar (3.90 and 3.89). It suggests that the most important risk factor of HCC in Qidong was HBV infection because it had a higher prevalence among the population while the HCV infection having an equal OR value was also a risk factor.

Persistent increase of hippocampal presynaptic axon excitability after repetitive electrical stimulation: dependence on N-methyl-D-aspartate receptor activity, nitric-oxide synthase, and temperature

The electrical excitability of Schaffer collateral axons and/or terminals was studied in hippocampal slices by monitoring single, CA3 pyramidal neurons activated antidromically from CA1 stratum radiatum. At 22 degrees C, weak, repetitive stimulation with as few as 10 impulses at 2 Hz led to a robust lowering of the antidromic activation threshold that lasted > 30 min. The effect was completely absent at 32 degrees C and was blocked by both the N-methyl-D-aspartate receptor antagonist, 2-amino-5-phosphonovalerate and the inhibitor of nitric-oxide synthase, L-nitro-arginine methyl ester. Such threshold lowering would alter the variance of synaptic responses from axons stimulated in the variable excitation region of their input-output functions. These results thus raise important doubts about the interpretation of experiments in which the so-called minimal-stimulation method has been used at reduced temperature to infer changes in quantal transmission during hippocampal long-term potentiation. In the present experiments, no changes were observed in the estimate of excitatory postsynaptic potential quantal content in long-term potentiation experiments at either temperature, which could not be accounted for by an artificial, temperature-dependent change in the responsiveness of presynaptic axons.

The fern Polypodium decumanum, used in the treatment of psoriasis, and its fatty acid constituents as inhibitors of leukotriene B4 formation

The fern Polypodium decumanum, commonly called Calaguala, has a clinically documented use in South America and Spain in the treatment of psoriasis. One of the inflammatory mediators isolated in abnormally high quantities in the psoriatic skin is leukotriene B4 (LTB4). Calaguala was tested in an in vitro model using human leukocytes for its ability to inhibit the LTB4 formation. The inhibition was found to be caused by the polyunsaturated fatty acids (PUFAs) linoleic, linolenic and arachidonic acid. IC50 values were determined for the isolated acids and compared to a group of closely related acids also commonly found in nature. The IC50 values for most acids tested were of the same magnitude (20-60 microM) except for arachidonic acid which showed stimulatory activity and 8(R) hydroxylinoleic acid which gave 30% inhibition with the highest dose tested (120 microM). The amounts of PUFAs in different Calaguala extracts were quantitatively analysed and it is concluded that the fatty acid constituents of Calaguala may contribute to the clinical effects of the extract.

Ultraviolet solid-state laser (213-nm) photorefractive keratectomy. In vivo study

BACKGROUND

The pulsed ultraviolet 213-nm solid-state laser has been demonstrated as an alternative to the gas argon-fluoride 193-nm excimer laser for photorefractive keratectomy (PRK). The authors studied the clinical course and histopathologic changes occurring in rabbit corneas after PRK with a 213-nm solid-state laser.

METHODS

The 213-nm output of neodymium:YAG frequency-quintupled laser was used to create 5-mm optical zone ablations in seven pigmented rabbit corneas. The radiant exposure was 250 mJ/cm2 delivered through a computer-controlled scanning delivery system with a spot size of 0.5 mm. The target ablation was 4.0 diopters with an estimated ablation depth of 40 microns. A clinical estimate of corneal epithelial healing and stromal haze was made at intervals over the 3-month study period. Animals were killed immediately after ablation, or at 10 days, 1 month, or 3 months after ablation. Corneal tissue was preserved for light microscopy and transmission electron microscopy at each study interval.

RESULTS

All corneas re-epithelialized within 10 days postoperatively. Anterior stromal haze was clinically visible at 3 days, increased until approximately 1 month, and then gradually decreased over the succeeding 2 months. Residual subepithelial haze was visible at 3 months. Results of histopathologic study documented normal epithelium healing over time; the basement membrane retained its regular thickness and hemidesmosomes were abundant at 3 months. The anterior stroma had an increased number of fibroblasts at 10 days, many of which remained until 1 month. A mild, transient, cellular reaction occurred throughout the thickness of the stroma and the endothelium.

CONCLUSION

Using the 213-nm ultraviolet solid-state laser with a scanning delivery system, PRK shows a similar clinical course and histopathologic findings to the 193-nm excimer PRK study in rabbits. It is a clinically viable procedure for refractive surgery and requires further human clinical trails to determine its efficacy.

Laser-induced photoacoustic signal phase study of stratum corneum and epidermis

Laser-induced photoacoustic signal phase was employed for measurements of optothermal parameters of pig abdomen stratum corneum and epidermis. The non-radiative relaxation time was found to be 28 ms and the thermal diffusion time was 370 ms, yielding a thermal diffusivity value of (4.1 +/- 0.8) x 10(-4) cm2 s-1. This value compares well with other literature values for skin obtained using photothermal techniques.

Clinical significance of elevated serum soluble interleukin-2 receptor in gastric cancer

This is China's pilot study in the assessment of the diagnostic value of serum soluble IL-2 receptor (sIL-2R) in gastric cancer. We measured its level by ELISA method in 45 patients with gastric cancer (without metastasis: 32; with metastasis: 5; recurrence: 8) 27 gastric ulcer, 27 superficial gastritis and 44 healthy controls. The mean-serum sIL-2R levels were significantly elevated in cancer patients, those with metastasis showed even higher levels than those without metastasis. These results suggested that sIL-2R can be used as a marker of host biological response in gastric cancer patients as well as a tumor marker for the diagnosis of the disease.

Fluid flow modulates vascular endothelial cytosolic calcium responses to adenine nucleotides

OBJECTIVE

To determine whether fluid flow influences the action of soluble vasoactive agonists on vascular endothelium.

METHODS

Confluent monolayers of bovine aortic endothelial cells (BAEC) were cultured on glass coverslips, prelabeled with the Ca(2+)-sensitive dye fura-2, and placed in a parallel-plate flow chamber designed to generate defined laminar fluid flow. Cytosolic free Ca2+ concentration ([Ca2+]i) in individual BAEC was monitored during perfusion with medium containing adenine nucleotide under defined flow conditions.

RESULTS

Continuous perfusion with ATP (0.3-3.0 microM) or ADP (0.1-1.0 microM) evoked repetitive oscillations in [Ca2+]i in individual BAEC. The frequency of the [Ca2+]i oscillations was dependent on both nucleotide concentration and levels of applied shear stress; at constant bulk concentration of nucleotide, the frequency increased with shear stress. Stopping flow in the continuous presence of agonists immediately extinguished the oscillatory response. Elimination of extracellular Ca2+ did not inhibit the [Ca2+]i oscillations. In the presence of nonhydrolyzable nucleotide analog, ATP gamma S or ADP beta S, application of flow resulted in similar shear-dependent [Ca2+]i oscillations, suggesting that flow modulation of the [Ca2+]i response was not simply due to depletion of ATP or ADP in the vicinity of BAEC monolayers as a result of hydrolysis of nucleotides by ectonucleotidases.

CONCLUSIONS

These findings suggest that local hemodynamic conditions may modulate the action of vasoactive agents on the vascular endothelium in vivo.

Spatial-dynamic population systems: analysis and projection

"In this paper a set of more-detailed multiregional population accounts is proposed to specify more realistically the exposure time of populations at risk for various components of population change. The concepts of population-time at risk and forward demographic rates based on the initial population are discussed. The relations of the forward demographic rates defined in this paper with the occurrence-exposure demographic rates are discussed. A more precise and straightforward multiregional population model is developed on the basis of forward demographic rates. The model is also expressed in the familiar matrix form of multiregional, cohort-survival models." Some applications of the model are made to data for China.

Na(+)-dependent high affinity uptake of L-glutamate in primary cultures of human fibroblasts isolated from three different types of tissue

Cultured human fibroblasts isolated from embryonic muscle, skin and peripheral nerve tissues were found to accumulate [3H]L-glutamate by a Na(+)-dependent uptake process strongly inhibited by several glutamate/aspartate analogues including D- and L-aspartate, D- and L-threo-3-hydroxyaspartate and L-trans-pyrrolidine-2,4-dicarboxylate but not D-glutamate. It was also reduced by elevated concentrations of K+, Rb+ and Cs+. The values of Km's were 5-20 microM, well within the 'high affinity' region. Variations in the capacity (Vmax) of [3H]L-glutamate uptake did not correlate with the origin (muscle, skin or nerve tissue) of the fibroblasts. The uptake characteristics suggest that it is mediated by a transport system similar to that commonly observed only in brain tissue.

Locus-specific variation in phosphorylation state of RNA polymerase II in vivo: correlations with gene activity and transcript processing

To investigate functional differences between RNA polymerases IIA and IIO (Pol IIA and Pol IIO), with hypo- and hyperphosphorylated carboxy-terminal repeat domains (CTDs), respectively, we have visualized the in vivo distributions of the differentially phosphorylated forms of Pol II on Drosophila polytene chromosomes. Using phosphorylation state-sensitive antibodies and immunofluorescence microscopy with digital imaging, we find Pol IIA and Pol IIO arrayed in markedly different, locus- and condition-specific patterns. Major ecdysone-induced puffs, for example, stain exclusively for Pol IIO, indicating that hyperphosphorylated Pol II is the transcriptionally active form of the enzyme on these genes. In striking contrast, induced heat shock puffs stain strongly for both Pol IIA and Pol IIO, suggesting that heat shock genes are transcribed by a mixture of hypo- and hyperphosphorylated forms of Pol II. At the insertion sites of a transposon carrying a hybrid hsp70-lacZ transgene, we observe only Pol IIA before heat shock induction, consistent with the idea that Pol II arrested on the hsp70 gene is form IIA. After a 90-sec heat shock, we detect heat shock factor (HSF) at the transposon insertion sites; and after a 5-min shock its spatial distribution on the induced transgene puffs is clearly resolved from that of Pol II. Finally, using antibodies to hnRNP proteins and splicing components, we have discerned an apparent overall correlation between the presence and processing of nascent transcripts and the presence of Pol IIO.

Identification of a cryptic gene associated with an insertion sequence not previously identified in Bacillus thuringiensis

After screening several Bt strains with a cryII toxin probe, clones from two strains were found to contain a cryptic cryIIB gene associated with an insertion sequence element belonging to the IS2/IS3 family. The lack of expression of this gene appears to result from mutation of the upstream orf2 gene which has been shown to be necessary for cryII expression.

Biophysical tools for structure-based drug design

The emerging understanding of the structural basis of biological function has made possible a new technology of rational drug design. This technology uses a combination of modeling and intensive computational tools, but also relies critically on direct structural methods for verification and to provide direction for new leads. The present work illustrates applications of this technology to ligand design for several model systems, including iterative modeling and crystallographic design of streptavidin ligands, ranking of streptavidin ligands using comparative molecular field analysis and ranking of thermolysin inhibitors using Poisson-Boltzman methods.

Immunologic abnormalities in children with acute Kawasaki disease

Spontaneous release of IgG, production of IgG, IgM and IgG subclasses induced by PWM in vitro, serum IgG, IgM, IgA and IgG subclasses were measured in 23 patients with acute Kawasaki disease (KD). The results showed that there was polyclonal B cell activation with significantly increased IgG1 and IgG3. As compared with 21 healthy controls, the mean activities of B cell growth factors (BCGFs), B cell differentiation factors (BCDFs) and interleukin 6 (IL-6) were significantly elevated. IL-6 activity was correlated with the production of IgG, IgG1, IgG3 and IgM, while BCGFs and BCDFs were also correlated with IgG1. The serum level of circulating tumor necrosis factor (TNF) determined in 16 patients with acute KD using double antibody ELISA was 1.86-8.83 micrograms/ml, but it was less than 1 microgram/L in normal controls. The clinical value of increased TNF in serum is discussed.

Tissue-specific alternative splicing of the Drosophila dopa decarboxylase gene is affected by heat shock

The Drosophila dopa decarboxylase gene, Ddc, is expressed in the hypoderm and in a small number of cells in the central nervous system (CNS). The unique Ddc primary transcript is alternatively spliced in these two tissues. We investigated whether Ddc splicing in the CNS is a general property of the CNS or a unique property of the cells that normally express Ddc by expressing the Ddc primary transcript ubiquitously under the control of an Hsp70 heat shock promoter. Under basal expression conditions, Ddc splicing shows normal tissue specificity, indicating that the regulation of Ddc splicing in the CNS is tissue specific rather than cell specific. Previous studies have shown that severe heat shock blocks mRNA splicing in cultured Drosophila melanogaster cells. Our results show that splicing of the heat shock-inducible Hsp83 transcript is very resistant to heat shock. In contrast, under either mild or severe heat shock, the splicing specificity of the heat shock-induced Ddc primary transcript is affected, leading to the accumulation of inappropriately high levels of the CNS splice form in non-CNS tissues. The chromosomal Ddc transcript is similarly affected. These results show unexpected heterogeneity in the splicing of individual mRNAs as a response to heat shock and suggest that the Ddc CNS-specific splicing pathway is the default.

A clinical trial of a slow-release formulation of acetylsalicylic acid in patients at risk for preeclampsia

The formation of thromboxane A2 (TXA2) in maternal and foetal cord serum was measured at birth in eight control patients and in 13 patients taking 100 mg of a slow-release formulation of acetylsalicylic acid. The serum concentrations of TXB2 (a stable end product of TXA2 hydrolysis) in both maternal and cord serum from patients who ingested the acetylsalicylic acid formulation were significantly lower (P < 0.01) than those in control subjects. Acetylsalicylic acid was not detected (< 30 ng ml-1) in maternal plasma from six mothers and in cord plasma from seven foetuses in the acetylsalicylic acid-treated group. The mean cord to maternal plasma concentration ratios for detectable acetylsalicylic acid and salicylate were 0.62 +/- 0.19 (s.d.) (n = 6) and 0.84 +/- 0.16 (n = 13), respectively. We conclude that low doses of acetylsalicylic acid given in a slow-release form to mothers during pregnancy cause depression of TXA2 formation in the foetal blood.

Clinical and experimental studies on shallow needling technique for treating childhood diarrhea

Treatment of diarrhea in children by shallow needling and by drugs was studied in 3 separate groups for comparison. For Group I, the lateral line II of the forehead was taken, i.e. the upper, middle and lower points of the line staring from Toulinqi (UB 15) vertically downwards to the place 1 cm below the hairline were selected. For Group II, shallow needling was done on body acupoints, the main points selected being Qihai (Ren 6), Shuifen (Ren 9), bilateral Tianshu (St 25), and bilateral Zusanli (St 36); the adjuvant acupoints were Taibai (Sp 3) and Gongsun (Sp 4). The depth of shallow needling was merely puncturing the skin. For Group III the drugs used were Liteling, Berberine, Gentamycin, Ampicillin, and SMZ Co. The results of treatment in Group I and II differed insignificantly, while both were significantly superior to drugs in Group III. Experimental studies also showed that shallow needling enhanced the humoral and cellular immunity and promoted the intestinal peristaltic function.

Regulation of adenine nucleotide concentration at endothelium-fluid interface by viscous shear flow

The action of adenine nucleotides on vascular endothelial cells is apparently mediated by the local flow conditions. Because nucleotides are sequentially degraded from ATP-->ADP-->AMP-->adenosine by ecto-enzymes at the endothelial surface, it has been hypothesized that the observed flow effect is caused by the flow-dependent change of nucleotide concentration at the cell surface. In this study, we have calculated the concentration profiles of adenine nucleotides at the cell surface under flow conditions encountered in an in vitro parallel-plate flow system, as has been used in several related experimental studies. When medium containing uniformly distributed ATP is perfused over endothelial monolayers, our results show that ATP concentration in the cell vicinity gradually decreases in the streamwise direction as a result of enzymatic degradation. This hydrolysis of ATP results in the generation of ADP, and ADP concentration in turn gradually increases at the cell surface. The concentration profiles of nucleotides are dependent on the levels of applied wall shear rate. As the corresponding shear stress increases from 0.1 to 30 dynes/cm2, ATP concentration at the cell surface at the center of coverslip increases from 0.66 to 0.93. Under no-flow conditions, our model predicts a steady decline of ATP concentration and a transient increase of ATP-derived ADP, comparable to the published results of previous experiments. These numerical results, combined with our recent experimental data, provide insights into the cellular mechanisms by which hemodynamic flow modulates the effects of vasoactive agents on endothelium.

Analysis of urban-rural population dynamics of China: a multiregional life table approach

This is the second of two papers in which the urban-rural population dynamics of China is analyzed. Urban-rural population life tables are constructed in this paper. The differential urban and rural population dynamics are revealed by the calculations of life expectations, net reproduction expectations, and net migraproduction expectations in the urban and rural regions of China.

Hemodynamic effects and the effective treatment of naloxone on experimental acute pancreatitis in dogs

Dog model of acute pancreatitis, induced by intrapancreatoductal injection of fresh trypsin-bile mixture, was used to investigate the effects of naloxone on hemodynamic changes in acute pancreatitis. In the control group, acute pancreatitis was induced and characterized hemodynamically by the decrease in maximum positive and negative dP/dt (+/- dP/dtmax), cardiac output (CO) and cardiac index (CI), and increase in pulmonary vascular resistance (PVR) and systemic vascular resistance (SVP), as well as early reduction of pancreatic blood flow (PBF). In the naloxone treated group, naloxone was given intravenously 10 minutes after the induction of acute pancreatitis (80 micrograms/kg as a bolus + 80 micrograms/kg/h for 3 hours). It was found that naloxone significantly increased PBF and the +/- dP/dtmax effectively prevented the significant decrease in CO, CI and increase in PVR, SVR observed in untreated acute pancreatitis; and significantly reduced the severity of pancreatitis, as assessed by both histological staging and mortality rate. These results suggest that naloxone appears to limit the progression from edematous to hemorrhagic pancreatitis through preserving PBF and improving systemic hemodynamics at the early phase of acute pancreatitis; hence the hypothesis that endogenous opioid peptides may play a role in the pathophysiology of acute pancreatitis.