Recent advances in lipid nanovesicles for targeted treatment of spinal cord injury

The effective regeneration and functional restoration of damaged spinal cord tissue have been a long-standing concern in regenerative medicine. Treatment of spinal cord injury (SCI) is challenging due to the obstruction of the blood-spinal cord barrier (BSCB), the lack of targeting of drugs, and the complex pathophysiology of injury sites. Lipid nanovesicles, including cell-derived nanovesicles and synthetic lipid nanovesicles, are highly biocompatible and can penetrate BSCB, and are therefore effective delivery systems for targeted treatment of SCI. We summarize the progress of lipid nanovesicles for the targeted treatment of SCI, discuss their advantages and challenges, and provide a perspective on the application of lipid nanovesicles for SCI treatment. Although most of the lipid nanovesicle-based therapy of SCI is still in preclinical studies, this low immunogenicity, low toxicity, and highly engineerable nanovesicles will hold great promise for future spinal cord injury treatments.

[Epidemiological research progress on the relationship between children's dietary patterns and health]

As food preferences and eating habits form early in life, the development of healthy eating habits in early childhood is a way to prevent diet-related diseases. The dietary pattern approach examines the effect of an overall diet on health outcomes, instead of individual foods or nutrients, thereby presenting a comprehensive evaluation of children's dietary intake. This article reviews the current literature to summarize the main methods for assessing dietary patterns and explore relationships between children's dietary patterns and obesity, puberty onset, cardiovascular diseases, and neurodevelopment. The purpose of this review is to provide evidence-based support for reducing the risk of diet-related diseases in children and recommendations for future research directions.

Ultrabright fluorescent microsphere and its novel application for improving the sensitivity of immunochromatographic assay

Fluorescent microsphere (FM) is widely used as probe in immunochromatographic assay (ICA). However, the performance of conventional FM is limited because of the aggregation-caused quenching effect. Herein, we compared a kind of conventional FM (DMFFM, loading DMF) with novel aggregation-induced emission FM (AIEFM, loading TCBPE). The fluorescence intensity of DMFFM initially increased and then decreased as the concentrations of the loading DMF increased. The fluorescence intensity of AIEFM increased as the concentrations of the loading TCBPE increased and retained a high value. AIEFM was compared with two commercial FMs purchased from Ocean (OFM) and Merk (MFM). The maximum fluorescence intensity and relative quantum yield of AIEFM was approximately 5 and 4.5 times higher than those of two commercial FMs. We used the novel AIEFM as a probe to improve the sensitivity of ICA. When Escherichia coli O157:H7 was detected as the target, the limit of detection of ICA based on AIEFM, OFM and MFM were 3.98 × 10³ CFU/mL, 4.48 × 10⁴ and 2.78 × 10⁴ CFU/mL, respectively. The ICA of AIEFM had 11 and 7 times improvement in sensitivity compared with that of OFM and MFM. Our results could be used as a basis for novel probes in practical ICA applications.

Advantages of time-resolved fluorescent nanobeads compared with fluorescent submicrospheres, quantum dots, and colloidal gold as label in lateral flow assays for detection of ractopamine

Label selection is a critical factor for improving the sensitivity of lateral flow assay. Time-resolved fluorescent nanobeads, fluorescent submicrospheres, quantum dots, and colloidal gold-based lateral flow assay (TRFN-LFA, FM-LFA, QD-LFA, and CG-LFA) were first systematically compared for the quantitative detection of ractopamine in swine urine based on competitive format. The limits of detection (LOD) of TRFN-LFA, FM-LFA, QD-LFA, and CG-LFA were 7.2, 14.7, 23.6, and 40.1pg/mL in swine urine samples, respectively. The sensitivity of TRFN-LFA was highest. In the quantitative determination of ractopamine (RAC) in swine urine samples, TRFN-LFA exhibited a wide linear range of 5pg/mL to 2500pg/mL with a reliable coefficient of correlation (R²=0.9803). Relatively narrow linear ranges of 10-500pg/mL (FM-LFA) and 25-2500pg/mL (QD-LFA and CG-LFA) were acquired. Approximately 0.005µg of anti-RAC poly antibody (pAb) was used in each TRFN-LFA test strip, whereas 0.02, 0.054, and 0.15µg of pAb were used in each of the FM-LFA, QD-LFA, and CG-LFA test strips, respectively. In addition, TRFN-LFA required the least RAC-BSA antigens and exhibited the shortest detection time compared with the other lateral flow assays. Analysis of the RAC in swine urine samples showed that the result of TRFN-LFA was consistent with that of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a commercial enzyme-linked immunosorbent assay (ELISA) kit.

Toxicity of Mycotoxins from Contaminated Corn with or withoutYeast Cell Wall Adsorbent on Broiler Chickens

This study investigated the effects of feeds naturally contaminated with mycotoxins on growth performance, serum biochemical parameters, carcass traits, and splenic heat shock protein 70 (Hsp70) mRNA expression levels in broiler chickens. The efficacy of yeast cell wall (YCW) adsorbent in preventing mycotoxicosis was also evaluated. Three hundred 1-d-old Arbor Acres broiler chicks were randomly allotted to 3 treatments in completely randomized design for 42 d. Each treatment group had 5 replicate pens with 20 birds. The treatments were as follows: i) basal diet (control), ii) naturally contaminated diet (NCD), and iii) NCD+0.2% YCW adsorbent (NCDD). The NCD decreased average daily gain (ADG) (p<0.01) of 0 to 21 d, 22 to 42 d, and 0 to 42 d, and increased feed conversion ratio (p<0.01) of 22 to 42 d and 0 to 42 d. Both the breast meat percentage and thigh meat percentage of the NCD group were significantly higher (p<0.01) than that of the control group on d 21. The NCD group showed significantly increased levels of triglycerides (p<0.05) and cholesterol (p<0.05) on both d 21 and d 42 compared to the control group. However, the NCD significantly reduced (p<0.01) the high-density lipoprotein (HDL) on d 42 compared to controls. Compared with the NCD, supplementation with YCW significantly improved (p<0.01) the ADG of 0 to 21 d and 0 to 42 d, and increased (p<0.01) concentrations of HDL on d 42, and on d 21, and triglycerides (p<0.05) on d 21 and d 42. Supplementation with YCW reduced (p<0.01) the breast meat percentage, the thigh meat percentage, the concentrations of cholesterol (p<0.01) and the low-density lipoprotein (p<0.05) on d 21, and improved (p<0.01) the splenic Hsp70 mRNA expression levels compared with the NCD group. The results of this study indicated that feeding NCD for 42 d had adverse effects on broiler chickens, and that YCW might be beneficial in counteracting the effects of mycotoxins.

Effects of naturally mycotoxin-contaminated corn on nutrient and energy utilization of ducks fed diets with or without Calibrin-A

One hundred sixty-two 21-d-old ducks were randomly allotted to 6 treatments with 3 levels of mycotoxin-contaminated corn (0, 50, and 100% M) and 2 levels of Calibrin-A (CA, a clay mycotoxin adsorbent, 0 and 0.1%) to evaluate the effects of increasing levels of mycotoxin-contaminated corn on nutrient utilization in ducks fed diets with or without CA. Endogenous losses were obtained from another 27 ducks. Excreta samples were collected to determine DM, OM, CP, amino acids, and gross energy. Gross energy was analyzed for computation of AME and TME. The apparent digestibility (AD) and true digestibility (TD) of the nutrients in all treatments with and without CA had common (P > 0.05) intercepts and slopes except Pro (P < 0.05). The AME, TME, AD, and TD of DM, OM, Phe, and Gly were linearly (P < 0.05) decreased as the concentration of contaminated corn in the diet increased. Ducks fed the 100% M diet supplemented with 0.1% CA increased AD and TD of Gly compared with the 100% M diet, and ducks fed 50 and 100% M diet supplemented with 0.1% CA increased AD and TD of Pro compared with 50% M and 100% M diet, respectively. In the present study, ducks fed mycotoxin-contaminated corn decreased nutrient digestibility in dose-dependent manner, and 0.1% CA supplementation improved AD and TD of Gly and Pro.

Effects of dietary supplementation of multi-enzyme on growth performance, nutrient digestibility, small intestinal digestive enzyme activities, and large intestinal selected microbiota in weanling pigs

Two experiments were conducted to assess the effects of dietary supplementation of an exogenous multi-enzyme (EME) preparation to 35- to 65-d-old piglets on apparent total tract digestibility (ATTD), growth performance, digestive enzyme activities, and selected microbial populations in feces. In Exp.1, twenty eight 35-d-old piglets were randomly assigned to 7 dietary treatments (corn-soybean based diet supplemented with 0, 100, 150, 200, 250, 300, or 350 mg EME/kg) in a 14-d digestibility study. Piglets fed the diets supplemented with EME had greater ATTD of DM, CP, and GE (P = 0.001, 0.005, and 0.009, respectively) than those fed the diet without EME supplementation, and those ATTD values increased linearly and quadratically (P < 0.001) as the levels of supplemented EME increased. In Exp. 2, two hundred 35-d-old weanling piglets were randomly allocated to 20 pens. The pens were then randomly assigned to 5 dietary treatments (corn-soybean based diet supplemented with 0, 100, 150, 250, or 350 mg EME/kg) with 4 pens per treatment in a 30-d feeding experiment. Piglets has ad libitum access to diets and water, and they were weighed at the beginning (35-d-old), middle (50-d-old), and end (65-d-old) of the experiment. Fecal samples were grabbed directly from the rectum and digesta samples from duodenum, jejunum, and ileum were taken at the end of the experiment for the analysis of selected bacteria populations and digestive-enzyme activities. The ADG and ADFI tended to be greater with the increasing levels of supplemented EME in both periods, whereas G:F was improved (P = 0.012 and 0.017) by EME in the period of 35 to 50 d of age and during the overall experimental period. Furthermore, inclusion of EME in diet increased the counts of Lactobacilli spp. and Bacillus subtilis spp., but reduced the populations of Salmonella spp. and Escherichia coli spp. in the feces. The EME supplementation also enhanced (P < 0.05) the activities of amylase, lipase, and protease in the small intestine. The growth performance-enhancing effects of EME appeared to be mediated by the age of the piglet and the dose of EME used. Supplementation of corn-soybean meal diets for 35- to 65-d-old piglets with EME has a potential to enhance gut health condition, increase nutrient digestion, and increase growth performance.

Toxicity of increasing aflatoxin B1 concentrations from contaminated corn with or without clay adsorbent supplementation in ducklings

A total of 1,280 1-d-old ducks were used in a study to investigate the effects of increasing aflatoxin B1 (AFB1) concentrations from naturally contaminated corn on young ducklings, and the effectiveness of a clay adsorbent (CA) to protect against those effects. Ducks were randomly allotted to 8 treatments (TRT) in a 4 × 2 factorial arrangement with 4 levels of AFB1 (0, 25, 50, and 100 μg/kg) and 2 levels of CA (0 and 0.1%) with 8 pens per TRT and 20 ducks per pen. All ducks were allowed ad libitum access to feed and water during the 21-d experiment. The ADG, ADFI, feed conversion rate, mortality, bill color, and CV of BW of each replicate were measured at the end of the study. Blood and tissue samples from 8 ducks per TRT were obtained on d 21 of the experiment to determine the serum immunoglobulin and protein concentrations, relative organ weights, and intestinal morphology. Average daily gain and relative weights of the liver, spleen, thymus, and bursa of Fabricius decreased linearly (P < 0.05) as dietary AFB1 increased. Serum proteins and intestinal villi heights and villus/crypt ratio followed the same pattern. Bill decolorization ratio, CV of BW, and mortality increased linearly (P < 0.05) as dietary AFB1 increased. Adding 0.1% CA to the diet improved (P < 0.05) the relative weights of the small intestine, spleen, and thymus, and the villus height and villus/crypt ratio of the duodenum and jejunum, as well as the serum IgG and IgM concentrations. Adding CA also reduced (P < 0.05) bill decolorization ratio, CV of BW, mortality, and serum IgA concentration. Therefore, duck performance was negatively affected by increasing AFB1 concentrations in diets. But the addition of 0.1% CA can protect against the detrimental effects caused by AFB1-contaminated corn in diets for ducks.

[Systematic surveillance of water body in schistosomiasis susceptible areas in Nanchang County by sentinel mice]

OBJECTIVE

To determine the status of cercariae of Schistosoma japonicum in water bodies of the Nanchang County section of Poyang Lake region.

METHODS

By using sentinel mice, the schistosome infectivity of water bodies was detected in 8 surveillance areas (59 experimental points in total) along the Fu River, Wuxing Farm, south branch of the Ganjiang River, and middle branch of the Ganjiang River from June to July 2011.

RESULTS

A total of 600 sentinel mice were placed in the experimental areas and 584 were retrieved, among which 577 mice were dissected and 1 mouse was infected with S. japonicum (4 worms collected), with the infection rate of 0.17%.

CONCLUSION

By using the sentinel mouse method to survey the water body schistosome infectivity, the status of Oncomelania snails should be mainly considered, and the infection rate of sentinel mice is affected by water situation, water level, flow velocity, etc.

[Comparison of knowledge, attitude and practice of students left at home or not on schistosomiasis prevention and control]

The questionnaire survey on knowledge, attitude and practice (KAP)of students left at home or not about schistosomiasis prevention and control showed that there were no statistically significant differences of the scores of KAP between the two groups of students (all P values were above 0.05).

Effects of ginger root (Zingiber officinale) on laying performance and antioxidant status of laying hens and on dietary oxidation stability

To investigate the effects of ginger root (Zingiber officinale) on laying performance and antioxidant status of laying hens and on dietary oxidation stability, 675 Hy-Line brown laying hens at 27 wk of age were randomly allocated to 5 treatments with 5 replicates in a complete randomized design. Laying hens were fed corn-soybean meal based diets and supplemented with 0, 5, 10, 15, or 20 g of ginger powder/kg of diet for 10 wk. The ADFI, laying rate, average egg weight, egg mass, and feed conversion of each replicate were measured weekly. Blood samples from 10 laying hens and 15 egg samples/treatment were obtained on d 35 and 70 of the experiment to determine the serum or egg yolk antioxidant enzymatic activities. Three separate batches of each treatment diet were also made at the beginning of the experiment and stored at 20°C. Subsamples were taken at 10-d intervals to determine the dietary oxidation stability over a 60-d period. All laying hens had similar ADFI, laying rate, average egg weight, and feed conversion. However, laying hens supplemented with ginger powder had higher (P = 0.024) egg mass than the control group. Supplementation of ginger powder increased (P < 0.05) the serum and egg yolk antioxidant enzymatic activities of laying hens on d 35 and 70. Increasing ginger powder from 0 to 20 g/kg of diet linearly increased (P < 0.05) the peroxide value but linearly reduced (P < 0.05) the acid value of lipid extracted from stored diets for the first 30 d, but not for the second 30 d. Dietary supplementation of ginger powder improved laying performance and serum and egg yolk antioxidant status and enhanced dietary oxidation stability in a dose-dependent manner. The optimum supplementation rate of ginger powder in the diet of laying hens appeared to be between 10 and 15 g/kg of diet.

[Survey on knowledge and attitude of schistosomiasis control among villagers in susceptible zones in Poyang Lake area]

OBJECTIVE

To understand the status of health education on schistosomiasis for residents in susceptible zone and provide a reasonable basis for related study.

METHODS

A questionnaire survey on knowledge, attitude about schistosomiasis of the residents was conducted.

RESULTS

Status of education on schistosomiasis of susceptible areas for the residents in general is not optimistic, the frequency of contacting with infected water was high, the demographic characteristics were also significant: (1) The passing rate for the villagers' schistosomiasis knowledge was too low, only 39.6%, the difference between awareness rates of schistosomiasis knowledge among villagers with different educational levels was significant (P < 0.05); (2) The overall level of correct attitude for schistosomiasis control was poor, only 37.7% of the villagers with a good attitude, the differences among villagers with different ages and occupations were significant (both P values < 0.05); (3) 73.5% of the villagers had ever contacted with infected water, and different groups contacted with infected water in different ways, 67.5% of men contacting for bathing, fishing, 63.7% of women contacting for washing clothes.

CONCLUSIONS

Health education for schistosomiasis control in susceptible zones should be strengthened, the reasons for differences in cognitive level about schistosomiasis control among the villagers with different demographic characteristics and the better models for educational interventions for different villagers need to be explored.

[Quantitative determination of icariin in "tangzhi shuangjiang cha" by high performance liquid chromatography]

Icariin in "Tangzhi Shuangjiang Cha" was quantitatively determined by HPLC with ODS column, a mixture of MeOH-H2O(60:40, V/V) as mobile phase and UV detection at 270 nm. There was a good linear relationship within the range of 0.1 g/L-0.5 g/L(r = 0.9993). The average recovery was 101.4%, RSD was below 2.7%(n = 3). The method is rapid, simple, accurate and reproducible. And the method is proposed to be used for quality control of "Tangzhi Shuangjiang Cha".

In situ dehydration of carbamazepine dihydrate: a novel technique to prepare amorphous anhydrous carbamazepine

The purposes of this project were to prepare amorphous carbamazepine by dehydration of crystalline carbamazepine dihydrate, and to study the kinetics of crystallization of the prepared amorphous phase. Amorphous carbamazepine was formed and characterized in situ in the sample chamber of a differential scanning calorimeter (DSC), a thermogravimetric analyzer (TGA), and a variable temperature x-ray powder diffractometer (VTXRD). It has a glass transition temperature of 56 degrees C and it is a relatively strong glass with a strength parameter of 37. The kinetics of its crystallization were followed by isothermal XRD, under a controlled water vapor pressure of 23 Torr. The crystallization kinetics are best described by the three-dimensional nuclear growth model with rate constants of 0.014, 0.021, and 0.032 min-1 at 45, 50, and 55 degrees C, respectively. When the Arrhenius equation was used, the activation energy of crystallization was calculated to be 74 kJ/mol in the presence of water vapor (23 Torr). On the basis of the Kissinger plot, the activation energy of crystallization in the absence of water vapor (0 Torr water vapor pressure) was determined to be 157 kJ/mol. Dehydration of the dihydrate is a novel method to prepare amorphous carbamazepine; in comparison with other methods, it is a relatively gentle and effective technique.

Evaluation of a commercial three-dimensional electron beam treatment planning system

We evaluated a commercial three-dimensional (3D) electron beam treatment planning system (CADPLAN V.2.7.9) using both experimentally measured and Monte Carlo calculated dose distributions to compare with those predicted by CADPLAN calculations. Tests were carried out at various field sizes and electron beam energies from 6 to 20 MeV. For a homogeneous water phantom the agreement between measured and CADPLAN calculated dose distributions is very good except at the phantom surface. CADPLAN is able to predict hot and cold spots caused by a simple 3D inhomogeneity but unable to predict dose distributions for a more complex geometry where CADPLAN underestimates dose changes caused by inhomogeneity. We discussed possible causes for the inaccuracy in the CADPLAN dose calculations. In addition, we have tested CADPLAN treatment monitor unit and electron cut-out factor calculations and found that CADPLAN predictions generally agree with manual calculations.

Physical properties of parabens and their mixtures: solubility in water, thermal behavior, and crystal structures

The peculiar solubility behavior of propylparaben (propyl ester of 4-hydroxybenzoic acid) in aqueous solution, when tested separately and together with methyl-, ethyl-, and butyl-parabens, has been investigated in detail. The results clearly indicate that the decrease in solubility (approximately 50% compared to the solubility value of propylparaben alone) is typical of those mixtures containing also ethylparaben, as demonstrated by solubility experiments on binary, ternary, and quaternary mixtures of the parabens. Phase diagrams of all the six binaries show that propylparaben and ethylparaben are the only pair that form almost ideal solid solutions near the melting temperatures. Moreover, phase-solubility analysis shows that propylparaben and ethylparaben, at room temperature, can also form solid solutions whose solubility is related to the composition of the solid phase at equilibrium. To achieve an independent confirmation of the possible solid solution formation that supports the above interpretation of the solubility behavior, the crystal structures of the four parabens have been examined and isostructurality has been found to exist only between ethylparaben and propylparaben. Powder X-ray diffraction has also been performed on ethylparaben, propylparaben, and their solid solutions obtained by recrystallization from water. The progressive shift of distinctive diffraction peaks with phase composition clearly indicates that propylparaben and ethylparaben form substitutional solid solutions. The small value (<1) of the disruption index provides thermodynamic support for substitutional solid solutions based on isostructural crystals.

Monte Carlo investigation of electron beam output factors versus size of square cutout

A major task in commissioning an electron accelerator is to measure relative output factors versus cutout size (i.e., cutout factors) for various electron beam energies and applicator sizes. We use the BEAM Monte Carlo code [Med Phys. 22, 503-524 (1995)] to stimulate clinical electron beams and to calculate the relative output factors for square cutouts. Calculations are performed for a Siemens MD2 linear accelerator with beam energies, 6, 9, 11, and 13 MeV. The calculated cutout factors for square cutouts in 10 X 10 cm2, 15 X 15 cm2, and 20 X 20 cm2 applicators at SSDs of 100 and 115 cm agree with the measurements made using a silicon diode within about 1% except for the smallest cutouts at SSD= 115 cm where they agree within 0.015. The details of each component of the dose, such as the dose from particles scattered off the jaws and the applicator, the dose from contaminant photons, the dose from direct electrons, etc., are also analyzed. The calculations show that inphantom side-scatter equilibrium is a major factor for the contribution from the direct component which usually dominates the output of a beam. It takes about 6 h of CPU time on a Pentium Pro 200 MHz computer to simulate an accelerator and additional 2 h to calculate the relative output factor for each cutout with a statistical uncertainty of 1%.

Incorporation mechanism of guest molecules in crystals: solid solution or inclusion?

Guest molecules (impurities or additives), together with some crystallization solvent, are often incorporated into the host crystals during crystallization from solution. The guest molecules may be incorporated either in solid solution or in liquid inclusions, or by both mechanisms. The mechanism of guest incorporation has been examined by a simple calculation method which is based on the equality of the guest/solvent mole ratio in the initial crystallization medium and in the putative inclusions. Application of this calculation method to eight guest+host systems described in the literature has shown that a negligible amount (at most 0.2%) of the guest molecules is incorporated into the crystal lattice in liquid inclusions. Therefore, it is concluded that the vast majority of the guest molecules are incorporated into the crystals in solid solution, as previously suggested, but hitherto unproven, for these guest-host systems.

Nucleation and crystallization kinetics of hydrated amorphous lactose above the glass transition temperature

The crystallization kinetics of amorphous lactose in the presence and absence of seed crystals were investigated at 57.5% relative humidity. Isothermal crystallization studies were conducted gravimetrically in an automated vacuum moisture balance at several temperatures between 18 and 32 degrees C. The crystallization rate constants were then determined from Johnson-Mehl-Avrami (JMA) treatment and isothermal activation energies were obtained from Arrhenius plots. Based on microscopic observations, a reaction order of 3 was used for JMA analysis. The nonisothermal activation energies were determined by differential scanning calorimetry using Kissinger's analysis. Isothermal activation energies for amorphous lactose with and without seed crystals were 89.5 (+/-5.6) kJ/mol and 186.5 (+/-17.6) kJ/mol, respectively. Nonisothermal activation energies with and without seed crystals were 71 (+/-7.5) kJ/mol and 80.9 (+/-8.9) kJ/mol, respectively. The similarity of the isothermal and nonisothermal activation energies for the sample with seeds suggested that crystallization was occurring by growth from a fixed number of preexisting nuclei. Markedly different isothermal and nonisothermal activation energies in the absence of seeds suggested a site-saturated nucleation mechanism, and therefore allowed calculation of an activation energy for nucleation of 317 kJ/mol.

Effects of changes in stopping-power ratios with field size on electron beam relative output factors

Stopping-power ratios are a function of field size and vary with accelerators. To investigate how these variations affect relative output factor measurements made using ion chambers for electron beams, especially for small fields, (L/rho)air(water) is calculated using the Monte Carlo technique for different field sizes, beam energies, and accelerators and is compared to the data in TG-21 or TG-25, which are for mono-energetic broad beams. For very small field sizes defined by cutouts, if the change in (L/rho)air(water) with dmax is ignored (i.e., TG-25 is not carefully followed), there is an overestimate of relative output factors by up to 3%. Ignoring the field-size effect on stopping-power ratio adds an additional overestimate of up to one-half percent, and using mono-energetic stopping-power ratio data instead of realistic beam data gives another error, but in the opposite direction, of up to 0.7%. Due to the cancellation of these latter two errors, following TG-25 with (L/rho)air(water) data for broad mono-energetic beams will give the correct answer for the ROF measurement within 0.4% compared to using (L/rho)air(water) data for which the field-size effect is considered for realistic electron beams.

Presence of antibodies to heat stress proteins and its possible significance in workers exposed to high temperature and carbon monoxide

Antibodies to the ubiquitous group of stress proteins known as heat shock proteins (Hsps) have been found to be associated with a number of diseases in humans. Hsps are known to be induced by certain xenobiotics, some of which are common in the working environment. The biological significance of the presence of such autoantibodies is presently unclear. In the present study, we used immunoblotting to investigate the presence of antibodies against the different stress proteins, Hsp27, Hsp60, Hsp71, Hsc (heat shock cognate) 73 and Hsp89 alpha and beta in groups of workers exposed to high temperature or carbon monoxide. These data were related to a detailed clinical evaluation and to various laboratory measurements including electrocardiogram (ECG), B echogram, white blood cell counts and typing, the activity of alanine aminotransferase (ALT), acid phosphatase (ACP) and alkaline phosphatase (ALP) and lymphocyte DNA damage. Antibodies to Hsp27 and Hsp71 were found more frequently in the high temperature and carbon monoxide-exposed groups than in controls (P < 0.05). The carbon monoxide-exposed group showed the highest incidence of anti-Hsp antibodies. Anti-Hsp60 antibodies were only detected in workers exposed to high temperature or carbon monoxide. The percentage of workers with abnormal ECG, B echogram changes and displaying hepatitis B antigen (HBsAg) was higher in the carbon monoxide group than in the control group (P < 0.05). There was a significant increase in the activity of ALT in the high temperature and carbon monoxide groups and in the activities of ACP and ALP in the carbon monoxide group (P < 0.05). The extent of DNA damage measured in lymphocytes was higher in workers from the high temperature and carbon monoxide-exposed groups. We suggest that the increased frequency of antibodies to Hsps is the result of these damages of the release of denatured Hsps and of a decrease in the phagocytic ability of macrophages in these workers. The data gathered in the present study show a statistical relation between the occurrence of antibodies against Hsps and the frequency of health problems in workers and suggest a potential role for the antibodies as useful biomarkers to assess whether workers are experiencing environmental stress.

The combined effects of high temperature and carbon monoxide on heat stress response

In this study, we have examined the effects of exposure to high temperature, carbon monoxide or a combination of both conditions in a model system, the rat and in industrial workers. In the rat liver, HSP70 mRNA and HSP70 synthesis were measured by dot hybridization and western blot. The results showed that after a heat stress HSP70 mRNA and its product, HSP70 increased significantly and there was a synergism in the combined effects of high temperature and carbon monoxide exposure on the induction of HSP70 mRNA and HSP70 synthesis. Heat played a major role in this induction. The presence of antibodies to human HSP27, HSP60, HSP70, HSC73, HSP89 alpha and beta in workers exposed to heat, carbon monoxide was also measured by western blot using purified HSPs as antigens. Plasma free amino acids were measured in the same group of workers. The incidence of antibodies to HSP27 and HSP70 was significantly higher in the workers working in an environment with extreme heat, and high carbon monoxide emission than in a control group. The carbon monoxide exposed group showed the highest incidence of antibodies to HSPs. Although our previous results indicated that workers had an insufficient protein intake, plasma free amino acids tended to increase, especially in methionine and tryptophan two kinds of amino acids which are absent from the main stress protein, HSP70. These results suggest that the major problems that these workers may face are how to facilitate the use of plasma free amino acids and reduce the inhibition of synthesis of normal proteins when they are exposed to occupational harmful factors. These results also add new information on the measurement of HSPs as a potential biomonitor to assess whether organisms are experiencing metabolic stress within their environment.

[An epidemiological study on the relationship between musculoskeletal disorders and work load]

965 workers engaged in working tasks of work intensity grade 2, 3, 4 (based on Chinese National Standard) were investigated on the musculoskeletal disorders with a questionnaire. The lumbar vertebra of 136 randomly chosen workers were also radiologically examined. The result revealed that the prevalence of low-back disorders was 51.2% on average and it was obviously correlated with such factors as age, standing, previous back injury, education level, sport activity, work intensity, working posture, satisfaction with the tools as well as work condition and house work. Heavy work load and unneutral working posture were proved to be the main factors as revealed by the multifactor analysis and further supported by the findings of X-ray examination.

Early health effects and biological monitoring in persons occupationally exposed to tetraethyl lead

Dependent on the level of occupational exposure to tetraethyl lead, the occurrence of early signs of toxicity and the urinary excretion of triethyl lead, diethyl lead and total lead compounds were investigated. This was done in the following cohorts in the province of Hubei, China: 277 workers at gasoline depots exposed to gasoline, 36 traffic policemen exposed to automobile exhaust and 342 public office workers (virtually non-exposed controls). Mean external tetraethyl lead exposure concentrations were 84.8 micrograms/m3 (as Pb) for the gasoline depot workers, 5.2 micrograms/m3 for traffic police and 1.1 microgram/m3 for the controls. No significant subclinical indications of organic lead toxicity were found in the group of traffic policemen compared with the controls. In the cohort of gasoline workers, however, there was a statistical increase (vs controls) in the frequency of appearance of tremor and of sinus bradycardia. When the cohort of gasoline workers was divided into subgroups of different ranges of exposure, dose-dependence was noted. In general, the urinary excretion of triethyl lead was very low compared to that of diethyl lead, which appears to be a sensitive and specific indicator of exposure to tetraethyl lead; total lead excretion did not correlate well with actual external tetraethyl lead exposure. On the basis of these data it seems that current occupational exposure limits for tetraethyl lead are inadequate and need to be revised. In addition, a biological limit, based on urinary diethyl lead excretion, may be proposed.

[DNA methylation of monohalogenated methanes of F344 rats]

Monohalogenated methanes (methyl chloride, methyl bromide and methyl iodide) are mutagenic and carcinogenic. The possible mechanism of these effects, DNA methylation, was studied. DNA adducts from organs of F344 rats exposed to these chemicals were separated and identified with high performance liquid chromatography (HPLC) and gas-chromatography/mass-spectrometry (GC/MS). DNA adducts, 7-methylguanine (7-MeG) and O6-Methylguanine(0(6)-MeG), incorporation of 14C into de novo synthesis of nucleobases could be observed in enzymatic DNA hydrolysates by HPLC and determination of the radioactivity in the fractions. The formation of DNA adducts in the studied organs was only quantitatively different. The formation of O6-MeG was further proved by analysing the acidic hydrolysates using HPLC with non-radioactive O6-MeG as internal standard. 7-MeG and 3-MeA were identified with GC/MS analysis.

Production of anti-tumor human monoclonal antibodies using different approaches

The production of anti-tumor human monoclonal antibodies (MAbs) by human-human or human-mouse hybridoma technology was studied. UC729-6, a human lymphoblastoid cell line, or NS-1, a mouse myeloma cell line, were fused with lymphocytes isolated from regional lymph modes of 26 patients with breast or gastrointestinal cancer, resulting in 130 immunoglobulin-secreting human-human hybrids and 21 human-mouse hybrids. The supernatants of 88 hybrids were screened against a panel of cancer cells. The supernatants of 37 human-human hybrids and 2 human-mouse hybrids reacted with cancer cell lines. After three times subcloning, only one anti-breast cancer hybrid human MAb, IgG(lambda) human-human hybridoma (MUBL-6), and one anti-gastric cancer human MAb, IgM(lambda) human-mouse hybridoma (HMG-1), were obtained. The antibody-secreting level was 1-4 micrograms/ml/24 h. Production of anti-breast cancer human MAbs by Epstein-Barr virus (EBV) hybridoma was also studied. Human lymphocytes were derived from draining lymph nodes of a breast cancer patient, whose serum antibody strongly reacted with tumor associated antigen (TAA). The enriched B cells were transformed with EBV in vitro. Positive antibody-secreting B cells were selected, expanded, and fused with heteromyeloma SHMD-33. The fusion frequency was 28/10(7) lymphocytes. Among them were 16 hybridomas secreting human immunoglobulin. After subcloning, 60% of the cloned hybridomas kept their antibody-secreting ability. Six observed hybridomas remained stable for more than 1 year in tissue cultures. The antibody-secreting level was 2.9-30 micrograms/ml/24 h. Supernatants from these hybridomas all reacted with breast cancer cell lines but not with gastric cancer cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic study of orally administered RU 486 in non-pregnant women

A method based on HPLC was devised for the estimation of RU 486 in blood and utilised to study the pharmacokinetics of a single dose of 50 mg RU 486 administered orally to 12 women on day 7 of the cycle. The dose was rapidly absorbed with peak plasma concentration between 1 and 2 hours. Distribution was also rapid (mean t1/2 alpha: 1.4h), whereas elimination was slow (mean t1/2 beta: 28.3 h). RU 486 was still detectable in some women at 72 h after administration. The plasma concentrations fitted the equation for a two-compartment open model from which the pharmacokinetic parameters were calculated. The mean total plasma clearance was 3.0 l/h, and the comparison of our data with those published studies suggests that the pharmacokinetics of RU 486 in Chinese women are similar to those of other populations.