Radiation-mediated control of drug delivery

Clinical trials of radiotherapy to control drug delivery were initiated in 1999 at Vanderbilt University. The initial studies exploited the findings that platelets are activated in tumor blood vessels after high-dose irradiation as used in radiosurgery and high-dose-rate brachytherapy. Platelets labeled with 111In showed binding in tumor blood vessels. However, the platelet labeling process caused platelets to also accumulate in the spleen. That clinical trial was closed, and subsequent clinical trials targeted protein activation in irradiated tumor blood vessels. Preclinical studies showed that peptide libraries that bind within irradiated tumor blood vessels contained the peptide sequence Arg-Gln-Asp (RGD). RGD binds to integrin receptors (e.g., receptors for fibrinogen, fibronectin, and vitronectin). We found that the fibrinogen receptor (GPIIb/IIIa, alpha2bbeta3) is activated within irradiated tumor blood vessels. RGD peptidemimetics currently in clinical trials include GPIIb/IIIa antagonists and the platelet-imaging agent biapcitide. Biapcitide is an RGD mimetic that is labeled with 99Tc to allow gamma camera imaging of the biodistribution of the GPIIb/IIIa receptor in neoplasms of patients treated with radiosurgery. This study has shown that the schedule of administration of the RGD mimetic is crucial. The peptide mimetic must be administered immediately before irradiation, whereas the natural ligands to the receptor compete for biapcitide binding if biapcitide is administered after irradiation. The authors currently are conducting a dose deescalation study to determine the threshold dosage required for RGD mimetic binding to radiation activated receptor. Radiation-guided clinical trials have been initiated by use of high-dose-rate brachytherapy. In a separate trial, the pharmacokinetics of radiation-inducible gene therapy are being investigated. In this trial, the radiation-activated promoter Egr-1 regulates expression of the tumor necrosis factor alpha gene, which is administered by use of the attenuated adenovirus vector. The Ad.Egr-TNF (ADGV) gene is administered by intratumoral injection of vector followed by irradiation in patients with soft-tissue sarcomas. This review highlights recent findings in these phase I pharmacokinetic studies of radiation-controlled drug delivery systems.

[Effects of angiotensin II on proliferation and expression of interleukin-6 of human kidney fibroblasts]

OBJECTIVE

To investigate the effects of Angiotensin(Ang) II on the proliferation and expression of Interleukin (IL)-6 in human kidney fibroblasts(KFB).

METHODS

The human KFB were cultured and identified, the proliferation of KFB was measured by MTT, and the level of IL-6 was measured by radioimmunoassay(RIA).

RESULTS

Angiotensin II could stimulate the proliferation of KFB and enhance the expression of IL-6 in protein level on KFB.

CONCLUSION

Angiotensin II can stimulate KFB's proliferation and enhance the expression of IL-6 of KFB. These findings suggest that Ang II might play a part in the mechanisms for modulating tubulointerstitial changes and induceing renal fibrosis.

[Intraspinal implantation of genetically modified myoblasts with brain-derived neurotrophic factor gene in treating spinal cord injury in rats: neurophysiological study]

OBJECTIVE

To observe the value of gene therapy to spinal cord injury in vivo by transferring gene of brain-derived neurotrophic factor (BDNF) to rat myoblast with retroviral vector electrophysiologically.

METHODS

Transection of spinal cord at the level of T9 was produced in 30 adult SD rats that were divided randomly into three groups: BDNF gene modified myoblast implantation (group A), myoblast implantation (group B), and no cell implantation as controls (group C). Three months after operation, whether the axon had regenerated and how the neural function was restored were observed, using the techniques of cerebral somatosensory evoked potential (CSEP) and motor evoked potential (MEP).

RESULTS

Three months after injury, 3 rats in group A showed CSEP signals and 5 rats MEP signals, but no electrophysiological response was found in group B or group C. The amplitudes of the recovery of CSEP or MEP signals decreased and their latencies increased as compared with those before injury. The neural function of the spinal cord was greater in group A than in B and C.

CONCLUSION

Treatment with genetically modified myoblasts producing BDNF can accelerate recovery from traumatic spinal cord injury in adult rats.

[A therapeutical approach by administering reduced glutathione to patients with uremic anemia]

OBJECTIVE

To verify the therapeutical effect of exogenous reduced glutathione (GSH) on the patients with uremic anemia.

METHODS

Forty two patients with uremic anemia were randomly divided into treatment group and control group. All patients received subcutaneously recombinant human erythropoietin (r-HuEPO) at the dose of 3000U twice a week for 12 weeks. Each of the patients in the treatment group was given intravenously reduced glutathione at the dose of 1200 mg twice a week for 12 weeks. The measurements of hemoglobin, red blood cells and hematocrit were performed.

RESULTS

After administration of r-HuEPO, the levels of hemoglobin, red blood cells and hematocrit were significantly elevated in both treatment and control groups (P < 0.01). The levels of hemoglobin, red blood cells and hematocrit in treatment group were elevated much more obviously, compared with those in control group (P < 0.05).

CONCLUSION

These findings seem to indicate that exogenous GSH could enhance the effect of r-HuEPO on uremic anemia, and therefore it might represent a useful drug in the treatment and management of uremic anemia.

The binding ability analysis of the normal VLDL receptor and its mutant

The ligand-binding domain of VLDL receptor contains eight imperfectly similar repeats. To discuss the contribution of each repeat to ligand binding, the RT-PCR technique was used to clone the VLDLR-cDNA from the heart muscle of Chinese people. Two recombinants were further constructed, which contained the full-length cDNA of VLDLR and the mutant lacking repeats 1-5. CHO cell line was transfected with two recombinants. The expression of VLDLR gene could be detected by RT-PCR from the CHO cells transfected with pCD-VR. The results of binding experiments showed that the ability of the CHO cells transfected with the full-length cDNA of VLDL-R binding DiI-labeled beta-VLDL was higher than that of the CHO cells transfected with the mutant. Our findings indicated that human VLDL-R gene could be expressed effectively on CHO cells, and the receptor was almost inactivated when repeats 1-5 were deleted.

Human vascular endothelial growth factor cDNA cloning and expression in osteoblasts

Human vascular endothelial growth factor (VEGF) cDNA was amplified by nested polymerase chain reaction method from the HL60 cells. Then a pCD-hVEGF165 recombinant plasmid was constructed. Rabbit osteoblasts were transfected with pCD-hVEGF165 plasmid by lipofectin mediated gene transfer. The transient expressive results were detected by immunohistochemical method. It was observed that the expression of human VEGF gene was detected 72 h after transfecting distinctly.

Cloning and identification of a novel variant of human vascular endothelial growth factor

A novel variant of human vascular endothelial growth factor (h'VEGF165) cDNA was amplified by nested PCR method from the HL601 cells and was cloned into a eukaryotic expressing vector pcDNA3 to construct a recombinant plasmid pCD-h'VEGF165. The amplified h'VEGF165 cDNA fragment was identified by enzyme digestion and DNA sequencing methods. Also, wild-type hVEGF165 cDNA was obtained, identified and cloned into a eukaryotic expressing vector pcDNA3 by using the same methods. The results of DNA sequencing showed that h'VEGF165 cDNA cloned from HL601 was 600 bp in size with 8% of the base sequence in h'VEGF165 cDNA being changed as compared with the base sequence in the wild-type hVEGF165 cDNA. The results of sequencing of hVEGF165 which was cloned from HL60 by us were consistent with the reports completely.

Microcalorimetric study of the toxic effect of sodium selenite on the mitochondria metabolism of Carassius auratus liver

The fundamental thermogenesis curves of the metabolic process of liver mitochondria from Carassius auratus and the toxic effect of Na2SeO3 on it were studied by using an LKB-2277 bioactivity monitor, ampoule method, at 28 degrees C. From the thermogenesis curves, the thermokinetic equations were established under different conditions. The kinetics show that a low concentration of Na2SeO3 (1-4 mg/L) had promoting action on the metabolism process of Carassius aurantus liver mitochondria, but that a high concentration of Na2SeO3 (8-16 mg/L) inhibited the mitochondria metabolism.

Characterization of peroxide ions in hydroxyapatite lattice

The incorporation of peroxide ions was confirmed in the heat treatment of hydroxyapatite (HA) powder under air as well as under oxygen atmosphere, by using X-ray diffraction, Raman, and infrared spectroscopy. Peroxide ions associated with vacancies were sited in the channel of HA lattice along the c-axis through the substitution of a portion of OH radicals. The molecular ions constituted a symmetric vibrator with a stretching vibration active in Raman spectrometry. This vibration was recorded at 750 cm(-1) in the Raman spectra of O(2)(2-)-containing HA samples. The final product was a solid solution of hydroxyl- and peroxide-apatite. However, the existence of peroxide ions in the HA lattice caused the contraction of the unit-cell dimensions of HA materials. In addition, a new hydrogen bond was formed between peroxide ions and adjacent OH radicals by using molecular spectroscopy analysis. During annealing treatment in air, peroxide ions decomposed and the substituted OH radicals re-enter the HA lattice, resulting in the elimination of the structural aberrations caused by the incorporation of peroxide ions. Concentration of the peroxide ions included in HA samples was measured by chemical analysis.

[The changes of serum angiotensin converting enzyme activity in Type 2 diabetes and its vascular complications]

This investigation was made with reference to the changes of serum angiotensin converting enzyme (SACE) activity in type 2 diabetes and its vascular complications. SACE activity was studied in 127 type 2 diabetic patients and 90 healthy persons by using a spectrophotometric assay. The results showed SACE activity was obviously higher in diabetic patients (459.51 +/- 175.85 U) than in healthy persons (321.14 +/- 121.27 U); SACE activity was significantly higher in type 2 diabetic patients with diabetic nephropathy (548.27 +/- 166.60 U) than in patients without diabetic nephropathy (383.2 +/- 139.00 U), but there was no difference between patients with microalbuminuria and macroalbuminuria; no statistical difference was detected in SACE activity between diabetic patients with diabetic retinopathy (465.64 +/- 178.93 U) and without retinopathy (449.07 +/- 170.04 U); SACE activity was not associated with the course of diabetes, blood pressure, blood lipid and blood glucose. These data suggest that raised SACE activity might only play a role in the initiation of type 2 diabetes and diabetic nephropathy, but not relate to the progress of diabetic nephropathy, the onset of diabetic retinopathy and hypertension.

[The epidemiological study of HIV infection among paid blood donors in one county of China]

OBJECTIVE

To observe the prevalence of HIV infection among paid blood donors and risk factors.

METHODS

Selected the residents between 18 to 50 years old from two villages in one county of China in 1997. We observed the prevalence of HIV infection and keep following them to 2000.

RESULTS

Nine hundred sixty-three residents were investigated and the prevalence of HIV was 1.8% (17/963). There were 88 paid blood donors among 963 interviewed subjects, the HIV prevalence was significantly higher (17.0% or 15/88) than those who didn't have the experiences of paid blood donations (0.2% or 2/875). Only one person out of 668 who were followed from 1997 to 2000 has converted to sero-positive, the incidence of HIV infection is 0.06 per 100 person-years. Nearly half of sero-negative and sero-positive people have the experiences of muscle injection. Among those with HIV-positive spouse, we found no one converted to sero-positive. The CD(4) count of those sero-positive people declined every year. HIV subtype and C2-V3 region sequence analysis were made for five HIV-positive people in 1998, the result indicated that all of them were infected with HIV-1 subtype B' and the genetic divergence rate was 2.4%.

CONCLUSION

There was a high prevalence of HIV among paid blood donors in some regions, and paid blood (plasma) donations were the main risk factor for HIV infection. Although no evidence suggests that during the follow-up period the epidemic of HIV infection has spread locally, it still shall take measurements to prevent further transmission of HIV through paid blood donors.

[Polymorphism of ACE gene and its relationship with serum ACE activity in the Hans in Chengdu region]

This study was aimed at the angiotensin converting enzyme (ACE) gene insertion/deletion(I/D) polymorphism distribution in Chinese and its relationship with serum ACE activity(SACE). SACE activity and ACE gene polymorphism in 90 healthy persons in Chengdu region were investigated using a spectrophotometric assay and the PCR technique, respectively. The results showed that, in the Hans, DD genotype of ACE gene was 18%, DI genotype 44%, and II genotype 38%. Allele frequencies were 0.40 for the D allele and 0.60 for the I allele. There were significant relationships between ACE I/D polymorphism and SACE activity. The results suggest that ACE genotype distribution be different between races, that II genotype and I allele be more frequent in Chinese, and that SACE activity be under the influence of a genetic polymorphism of ACE in Chinese.

[The effect of heparin on mesangial cells proliferation and cytokines production]

The human glomerular mesangial cells(MC) proliferation and cytokines secretion were detected by using MTT method and biological active method so as to assess the effects of heparin on the cultured human glomerular MC induced by lipopolysaccharides (LPS). The results showed that there were basic production of interleukin-6(IL-6) and tumor necrosis factor-alpha (TNF-alpha) on MC in the control group without LPS, that high-concentration heparin(500 U/ml) increased the effects of LPS on MC, and that low-concentration heparin (5 U/ml) conversely inhibited the effects of LPS on MC. These data indicate that the low-concentration heparin could inhibit the proliferation of MC and the secrection of IL-6 and TNF-alpha induced by LPS, and hence provide an experimental evidence for administration of heparin in the treatment glomerular disease.

[The survey of HIV prevalence among drug users in Guangxi, China]

OBJECTIVE

To understand the distribution and related risk factors of HIV infection among drug users in Guangxi.

METHOD

Three hundred and twenty five drug users were tested for serum HIV antibody, with enzyme linked immunosorbent assay.

RESULTS

One hundred and sixteen drug users (35.7%) were found to be HIV positive. The main risk factors associated with HIV infection were intravenous drug users and needle sharing among drug users. The HIV prevalence was 40.9% (114/279) among IDUs, and only 4.3% (2/46) among oral drug users. The phenomenon of sharing injecting equipment (76.7%) among intravenous drug users in Guangxi represents a very serious problem.

CONCLUSION

There is a high risk of HIV infection among drug users in Guangxi. Prevention programs urgently need to be implemented.

[The natural history of HIV infection among IDUs in Ruili, Yunnan province, China]

OBJECTIVE

To study the natural history of HIV infections among intravenous drug users.

METHODS

Six hundred and twenty five HIV infected people in Ruili, Yunnan province were observed. Retrospective data was analysed combined with a cross - sectional survey.

RESULTS

The number of death was 190 among 625 HIV - positive people. The cumulative death rate among HIV infected persons was 76.9 per 1,000 person - year, and the AIDS related death rate was 19.8 per 1,000 person - year. The median survival period of HIV infected persons was 9 years, and the median incubation period was about 8 years.

CONCLUSION

Of HIV infected people in Ruili, the median survival and incubation period were shorter compared with those in the United States and Western Europe.

[Effect of emodin on human kidney fibroblast proliferation]

OBJECTIVE

To study the effect of emodin on proliferation of human kidney fibroblasts in vitro.

METHODS

After human kidney fibroblasts were cultured, isolated and identified, both the effects of five different concentrations of emodin (10, 30, 50, 80 and 100 micrograms/ml) on 3H-TdR incorporation, and the effects of three different concentrations of emodin (10, 50 and 100 micrograms/ml) on cell cycle by flow cytometry were investigated.

RESULTS

The exposure of human kidney fibroblasts to emodin (10-100 micrograms/ml) caused a dose-dependent reduction in 3H-TdR (r = 0.995, P < 0.01), and could delay the progress of human kidney fibroblasts from G1 to S phase.

CONCLUSIONS

Emodin inhibited the proliferation of human kidney's fibroblasts by inhibiting the cell DNA synthase and delaying the progress of cell cycle. These findings might provide part of experimental basis for the clinical use of emodin.

Microcalorimetric study of Escherichia coli growth inhibited by the selenomorpholine complexes

The inhibitory or antibiotic action of four kinds of the selenomorpholine complex on a strain of Escherichia coli was studied by microcalorimetry. Differences in their capacities to inhibit the metabolism of this bacterium were observed. The extent and duration of the inhibitory effect on the metabolism as judged from the rate constant, k, and the half-inhibitory concentration, IC50, varied with the different drugs. The rate constant (k) of Escherichia coli (in the log phase) in the presence of the drugs decreased with increasing concentrations of the drugs (C). The relationship of k and C is nearly linear for (1) selenomorpholine and (2) selenomorpholine hydrochloride, but for (3) N,N'-methylene bisselenomorpholine and (4) N-dodecyl selenomorpholine, it is not linear. The experimental results reveal that the sequence of antibiotic activity of selenomorpholines is (3) and (4) > (1) > (2).

Cloning and expression of rat transforming growth factor beta 1 cDNA in osteoblasts

Rat transforming growth factor beta 1 (rTGF beta 1) cDNA from rat lymphocytes was cloned by RT-PCR and inserted into pcDNA3 to construct an eukaryotic expression vector, which was named pcDNA3-TGF beta 1. The cloned gene was confirmed to code rat TGF beta 1 by restriction enzyme analysis. pcDNA3-TGF beta 1 plasmid was transfected into rat osteoblasts by using liposome-mediated gene transfer technique and the expression of TGF beta 1 was detected by using immunohistochemical staining assay. It was found that the rat TGF beta 1 expression product was obviously detectable in the transfected osteoblasts in 48 h. High expression of TGF beta 1 was obtained in the rat osteoblasts in which the constructed TGF beta 1 expression vector was transfected.

Investigation of the distribution and changes of VLDLR subtype in fibrotic cardiac muscles

Very low-density lipoprotein receptor (VLDLR) is the major receptor with which cells can uptake the triacylglycerol from blood. It is divided into two subtypes according to presence of O-linked sugar domain located in the VLDLR receptor immediately outside of the membrane. Type I VLDLR contains the O-link domain, while type II has no such domain. The type I VLDLR are mainly found on the surface of human myocardial cells. The result of our quantitative polymerase chain reaction on the normal and fibrotic cardiac muscles showed that both subtypes and expression level of VLDLR on the myocardial cell surface did not vary significantly between the normal and the fibrotic cardiac muscles despite the presence of malfunction due to fibrosis. This finding suggests that fibrosis doesn't exert significant influence on the subtype and the expression of VLDLR on the surface of myocardial cells. Such inconsistence with the changes found in other fibrotic tissues is awaiting further studies.

[A comparative study of three-dimensional movements of lumbar spine in the old and the young people]

This article is aimed at the differences in lumbar vertebral three-dimensional movement and in stability between the old and the young people, and at the reasons which lead to the differences. Fifteen fresh adult male cadavers were divided into two groups: the young group, 20-30 years old, comprising 7 cases; the old group, 60-70 years old, 8 caes. Lumbar spine(L1-S1) was cut down. Three-dimensional movements under a loading system were measured by a compute system. The result showed that the range of the motion of the old group was lower than that of the young group. It suggests that the lumbar spine of the old people is more stable than that of the young people. This may be associated with the degeneration of the lumbar vertebra, which arouses biocompensatory changes, so the lumbar spine becomes re-stable.

Magnetite Nanoparticles Prepared by Precipitation from Partially Reduced Ferric Chloride Aqueous Solutions

Spherical magnetite particles with mean diameter of about 10 nm or less were prepared by means of a reduction-precipitation method with ferric chloride as starting material, which was partially reduced to ferrous salts by Na2SO3 before alkalinizing with ammonia. It was found that the nature of the product depends strongly on the initial ratio R0 = [Fe3+]0/[SO2-3]0. The most appropriate ratio was 3 as proved by X-ray diffraction analysis on the samples although the initial concentration of ferric chloride can be different. Particle diameter increased from ca. 3 to ca. 11 nm with an increase of the concentration of aqueous ferric chloride from 0.075 to 0.45 mol dm-3. The advantage of this method lies in the formation of a red intermediate during the reduction process, which enables us to prevent the reoxidation of the ferrous ions by adding precipitation agents at the end of the reduction reaction without the protection of nitrogen or argon. Copyright 1999 Academic Press.

[Protection of spinal motorneurons of section sciatic nerve by transplantation of NT-4 genetically expression cells into the side of section]

The NT-4 genetically engineered cells were made by infecting L-6TG cell (a rat myoblast cell line) in vitro with a retroviral vector pN2A containing the rat NT-4 cDNA. The bioactivities were determined by bioassay of PC12 cell survival rate. The rat with left sciatic nerve transaction was used as a model for treatment by implanting NT-4 genetically modified cell. The condition of motorneurons was assessed by Nissl stain and ChE stain. The results showed that: (1) the percentage of surviving Nissl-stained neurons on the lessened side of NT-4 (+) grafts significantly increased as compared to that with NT-4 (-) grafts 2-3 weeks and 3 months after sciatic nerve transaction, and (2) the grafted cells produced significant increase in the positive ChE stained area after sciatic nerve transaction in 1-3 weeks. Our observations indicate that adult motor neurons are still able to respond to neurotrophic factors and they may require the factors for survival.

Rheologic determinant changes of erythrocytes in Binswanger's disease

BACKGROUND

Binswanger's disease (BD) has been associated with severe arteriosclerotic changes in the long perforating arteries and with impaired cerebrovascular responsiveness to hypercapnia. Rheology parameters may become important factors in regulating cerebral blood flow. The purpose of this study was to investigate the changes in rheologic determinants of erythrocytes and to discuss the relation of erythrocytes and white matter lesions in this type of dementia.

METHODS

Twenty-eight patients suffering from BD and a control group matched for age, sex and cerebrovascular risk factors were tested for the following hemorheologic variables: erythrocyte deformability, erythrocyte membrane fluidity, erythrocyte aggregation, plasma viscosity and whole blood viscosity. Additionally, red cell membrane metabolic parameters, lipids and individual membrane phospholipids, sialic acid (SA) and malondialdehyde (MDA) contents, and ATPase activities were measured.

RESULTS

A significant decrease in erythrocyte deformability, erythrocyte membrane fluidity, membrane phosphatidylethanolamine, membrane phosphatidylcholine, membrane SA and membrane ATPase activities, and a significant increase in membrane cholesterol, cholesterol to total phospholipid ratio, MDA, broad viscosity and erythrocyte aggregation were observed in BD patients when compared with those of the matched control group.

CONCLUSIONS

Changes in erythrocyte membrane parameters, especially in phospholipids, can produce serious metabolic disorders and influence the rheologic properties of erythrocytes in patients with BD. These alterations can contribute to a circulatory slowdown and may lead to worsening of the condition of the cerebral white matter in these patients.

Physical and genetic interactions between Alx4 and Cart1

Alx4 and Cart1 are closely related members of the family of transcription factors that contain the paired-type homeodomain. In contrast to other types of homeodomains, the paired-type homeodomain has been shown to mediate high-affinity sequence-specific DNA binding to palindromic elements as either homodimers or as heterodimers with other family members. Alx4 and Cart1 are co-expressed at several sites during development, including the craniofacial mesenchyme, the mesenchymal derivatives of neural crest cells in the first branchial arch and the limb bud mesenchyme. Because of the molecular similarity and overlapping expression pattern, we have analyzed the functional and genetic relationships between Alx4 and Cart1. The two proteins have similar DNA-binding activity in vitro and can form DNA-binding heterodimers; furthermore, they activate transcription of reporter genes that contain high-affinity DNA-binding sites in cell culture in a similar manner. Therefore, at least by these criteria, the two proteins are functionally redundant. Analysis of double mutant animals reveals several genetic interactions. First, mutation of Cart1 exacerbates Alx4-dependent polydactyly in a manner that is dependent on gene dosage. Second, there are complex genetic interactions in the craniofacial region that reveal a role for both genes in the fusion of the nasal cartilages and proper patterning of the mandible, as well as other craniofacial structures. Third, double mutant mice show a split sternum that is not detected in mice with any other genotype. Interpreted in the context of the biochemical characterization, the genetic analysis suggests that Alx4 and Cart1 are indeed functionally redundant, and reveal both unique and redundant functions for these genes in development.

Preliminary study on the cooperation of IL-6 and mB7-1 in the induction of effective antitumor immunity in vitro

To find a new way for gene therapy against tumors with weak immunogenicity, the effect of mB7-1 costimulation alone, or combined with IL-6, in inducing antitumor immunity in vitro was investigated. It was found that mB7-1 cD-NA transfected B16 cells (B16-mB7-1) induced the expansion of effector lymphocytes and the generation of specific lytic activity more effectively than wild type B16 melanoma cells (B16-wt) or mock-transfected B16 cells (B16-neo) did. (P < 0.01), IL-6 could effectively stimulate lymphocytes proliferation, but failed to enhance its cytotoxicity, while the combination of mB7-1 and IL-6 increased both lymphocyte proliferative response and T-cell-mediated cytotoxicity more significantly than B7-1 or IL-6 did alone (P < 0.01). It was inferred that the costimulatory molecule B7-1 is required for the activation and proliferation of T lymphocytes; the expression of mB7-1 in tumor cells could increase their immunogenicity and induce effective antitumor immune response, and the combination of B7-1 and IL-6 could induce more effective antitumor immunity, indicating that cooperation of IL-6 and mB7-1 plays a role in T lymphocyte activation.

[Study of arginase activity in alveolar macrophages from patients with lung cancer]

Alveolar macrophages (AM) were obtained from 20 patients with primary lung cancer and 20 cases with nonmaligment pulmonary disease by BAL and were incubated in vitro in medium with and without BCG and/or IFN-alpha. Then the cell-free supernatants were harvested. The activity of arginase was assayed. It was found that: arginase was produced spontaneously by AM: The spontaneous production of arginase is lower in AMs from the tumor-bearing segments than either nontumor-bearing segments or AMs from the patients with nonmalignant pulmonary diseases (P < 0, .05). The production of arginase was icreased on AMs from the tumor-bearing segments stimulated with BCG and/or IFN-alpha (P < 0.05 or 0.01). The results suggested that (1) There are some function at defects of tumor. (2) The mechanism of anti-tumor and anti-infection activity of BCG and IFN-alpha may possibly increase the production of arginase of AMs.

[The effect of elevated hydrostatic pressure on expression level of type III collagen mRNA by lamina cribrosa cells in vitro]

OBJECTIVE

To investigate the effect of elevated hydrostatic pressure on the expression level of type III collagen mRNA by lamina cribrosa cells (LCCs) and approach the action of changes of extracellular stroma on glaucomatous optic nerve damage.

METHODS

LCCs were cultured and submitted to elevated hydrostatic pressure (4.67 - 5.33 kPa). We observed collagen type III mRNA level by dot-blot hybridization and computer imaging analysis.

RESULTS

Under the pressure for 3 days, the amounts of collagen III mRNA were 0.5828 +/- 0.0517 in optical density (OD), compared with the same period controls (0.2832 +/- 0.0613), the difference was statistically significant (P < 0.05). When exposed to pressure up to 6 days, the collagen III mRNA level remained somewhat higher than that of the control, but there was no significant difference (P > 0.05). After 9 to 12 days of exposure to pressure, the mRNA amounts were decreased respectively to 0.3246 +/- 0.0957 and 0.2164 +/- 0.0171 in OD that were lower than that of the control in the respective same periods, and the differences between the experimental and the control had no significance (P > 0.05).

CONCLUSION

Elevated hydrostatic pressure may increase expression level of collagen III mRNA by LCCs in a certain period.

Mutations in mouse Aristaless-like4 cause Strong's luxoid polydactyly

Mutations that affect vertebrate limb development provide insight into pattern formation, evolutionary biology and human birth defects. Patterning of the limb axes depends on several interacting signaling centers; one of these, the zone of polarizing activity (ZPA), comprises a group of mesenchymal cells along the posterior aspect of the limb bud that express sonic hedgehog (Shh) and plays a key role in patterning the anterior-posterior (AP) axis. The mechanisms by which the ZPA and Shh expression are confined to the posterior aspect of the limb bud mesenchyme are not well understood. The polydactylous mouse mutant Strong's luxoid (lst) exhibits an ectopic anterior ZPA and expression of Shh that results in the formation of extra anterior digits. Here we describe a new chlorambucil-induced deletion allele, lstAlb, that uncovers the lst locus. Integration of the lst genetic and physical maps suggested the mouse Aristaless-like4 (Alx4) gene, which encodes a paired-type homeodomain protein that plays a role in limb patterning, as a strong molecular candidate for the Strong's luxoid gene. In genetic crosses, the three lst mutant alleles fail to complement an Alx4 gene-targeted allele. Molecular and biochemical characterization of the three lst alleles reveal mutations of the Alx4 gene that result in loss of function. Alx4 haploinsufficiency and the importance of strain-specific modifiers leading to polydactyly are indicative of a critical threshold requirement for Alx4 in a genetic program operating to restrict polarizing activity and Shh expression in the anterior mesenchyme of the limb bud, and suggest that mutations in Alx4 may also underlie human polydactyly.

[Effect of yuanhua on isolated uterine strips in unpregnant rats]

OBJECTIVE

To explore the mechanism on the effect of Yuanhua on the contractile activity of isolated uterine strips in rats under artificial oestrum.

METHOD

Isolated strips were suspended in a tissue chamber in which Yuanhua was added with some antagonists of inhibitors or without.

RESULT

Yuanhua could excite the uterine smooth muscle strips in a dose-dependent manner, but atropine, phentolamine, hexamethonium and diphenhydramine could not inhibit this exciting action. This exciting effect could be inhibited completely by verapamil and decreased by indomethacin(inhibitor of prostaglandin synthase).

CONCLUSION

The exciting effect of Yuanhua on un-pregnant rats in vitro might be related to an action on the cell membrane Ca2+ channel as well as to a partial stimulation of synthesis and release of PG.

Alx-4: cDNA cloning and characterization of a novel paired-type homeodomain protein

Homeodomain containing transcription factors serve important functions in patterning the embryo during vertebrate development. We have isolated cDNA clones encoding a novel protein, named Alx-4, that contains a paired-type homeodomain. Analysis of the homeodomain sequence shows that Alx-4 belongs to a family of genes that are related to the Drosophila gene aristaless, and includes the mammalian genes Alx3, Cart-1, MHox, and S8. We have analyzed the expression of Alx-4 during development by Northern blot and whole mount in situ hybridization. In addition, we have generated antibodies to recombinant Alx-4 protein and identified Alx-4 protein in nuclear extracts prepared from mouse embryos. The expression pattern of Alx-4 suggests that it may play a role in the patterning of structures derived from craniofacial mesenchyme, the first branchial arch, and the limb bud. Our results provide a starting point for the analysis of a new member of the family of paired type homeodomain proteins.

Study of heat shock protein HSP90 alpha, HSP70, HSP27 mRNA expression in human acute leukemia cells

The expression of three heat shock proteins (HSPs)-HSP90 alpha, HSP70, HSP27 in cells obtained from 22 patients with leukemia, K562 erythroleukemia cell line, and normal blood cells was observed by means of RNA dot blot analysis. The results showed that the expression of the HSP27 gene was enhanced in 4 cases of acute lymphoid leukemia (ALL), 7 cases of acute nonlymphoid leukemia (ANLL) and 2 cases of myelodysplastic syndrome (MDS) as compared with that of the normal blood cells, yet there was no significant difference in the HSP27 expression between the ALL and ANLL cells. The expression of HSP70 in all the 5 ALL and ANLL patients was much lower than that of the normal subjects, except 1 case of ALL and 1 case of MDS, in which the expression was obviously enhanced. All the cases including 11 ANLL, 5 ALL and 1 MDS had higher HSP90 alpha expression than the normal subjects. The enhanced expression of HSP90 alpha in leukemia cells may be associated with the active and indefinite proliferation of leukemia cells. Our results also suggest that the high expression of the HSP27 gene may not be confined to a specific type of acute leukemia.

Osteogenic responses to extraskeletally implanted synthetic porous calcium phosphate ceramics: an early stage histomorphological study in dogs

In this experiment, synthetic porous calcium phosphate ceramics (hydroxyapatite-tricalcium phosphate) were prepared and implanted in dorsal muscles of dogs. The purpose was to study the biological processes prior to and during the morphogenesis of bone in extraskeletally implanted porous calcium phosphate ceramics. Specimens were harvested after implantation for 7, 15, 30, 45, 60, 90 and 120 days. Decalcified and undecalcified sections were prepared for alkaline phosphatase (ALP) histochemical localization and comparative histological analysis. The results show that bone morphogenesis in the pore regions of the extraskeletally implanted ceramics follows a complex process involving clot formation, vascular invasion, granulation-like tissue formation, polymorphic cell aggregation, osteoblast differentiation and bone formation. The characteristic feature preceding bone formation was polymorphic cell aggregation on the pore inner surface and near the invading capillaries or small venules. These cells were of various sizes and shapes, and some of them were positive for ALP activity. ALP-positive cell aggregates were more numerous where capillaries or venules were close to the pore inner surface. Osteoblast differentiation occurred within the cell clusters aggregated on the pore inner surface and bone matrix was secreted in direct contact with the ceramics. During bone formation, capillaries or small venules were always found close to the developing fronts of the osseous nidi. It is suggested that those cells which first appeared near the invading vasculature, the cells which aggregated on the pore inner surface and those cells which finally differentiated into osteoblasts may be interrelated in some way.

Polydactyly and ectopic ZPA formation in Alx-4 mutant mice

Correct development of the limb is dependent on coordination between three distinct signaling centers. Recently, fibroblast growth factor-4 has been identified as a crucial determinant of AER function, which directs limb bud outgrowth, and Sonic hedgehog has been identified as a signaling molecule that mediates ZPA function, which specifies anterior-posterior patterning in the developing limb bud. In addition, Shh and FGF-4 reciprocally reinforce each other's expression via a positive feedback loop, providing a molecular basis for the coordination of limb bud outgrowth and anterior-posterior patterning. The mechanisms by which these signaling centers come to occupy their normal positions in the posterior limb bud during development are not understood. Here we identify and characterize Alx-4, a gene that encodes a paired-type homeodomain protein. Alx-4 is expressed in several populations of mesenchymal cells, including mesenchymal cells in the anterior limb bud, and mice homozygous for targeted disruption of the Alx-4 gene have multiple abnormalities, including preaxial polydactyly. The polydactyly is associated with the formation of an ectopic anterior ZPA, as indicated by anterior expression of Sonic hedgehog, HoxD13 and fibroblast growth factor-4. The expression of other candidate regulators of anterior-posterior positional information in the limb bud, including HoxB8 and Gli3, is not altered in Alx-4 mutant embryos. By chromosomal mapping experiments, Alx-4 is tightly linked to Strong's luxoid, a polydactylous mouse mutant. The results identify Alx-4 as a determinant of anterior-posterior positional identity in the limb and a component of a regulatory program that restricts ZPA formation to the posterior limb bud mesenchyme.

Microcalorimetric study of the toxic effect of selenium on the mitochondrial metabolism of Cyprinus carpio liver

The metabolic thermograms and heat output of mitochondria isolated from carp liver have been determined by using an LKB bioactivity monitor. The thermogram can be divided into four parts: the lag phase, active recovery phase, stationary phase, and decline phase. The thermokinetic equation was established for the active recovery and decline phase of metabolism as follows: dP/dt = k(m)P (1-SP). The rate constants k1 and k2 of two phases of active recovery and decline phase have been also calculated. The metabolism activity of mitochondrial inhibited by a high concentration of trace element selenium has been studied. The metabolic heat released, time of each phase, and rate constants can be significantly influenced by excess of selenite added. These results suggested that a high concentration of selenium can damage the structure and function of mitochondria, and thus influence their metabolism.

Raised concentration of serum bile acids following occupational exposure to halogenated solvents, 1,1,2-trichloro-1,2,2-trifluoroethane and trichloroethylene

OBJECTIVES

The objectives of this study were threefold. First, to examine the hepatic effects of occupational exposure to 1,1,2-trichloro-1,2,2-trifluoroethane (FC 113) using conventional and newer tests (serum bile acids) of hepatobiliary function. Second, to assess the effects of altered work practices that included a reduced exposure to a different halogenated solvent (trichloroethylene) on the same parameters of liver function; and finally, to gather further data to support or refute the contention that serum bile acid (SBA) levels could provide a sensitive biological marker of exposure to these solvents.

DESIGN

Two groups of workers (control and exposed) in an Australian steel industry participated in the study. The exposed group (n = 5-6) comprised individuals who had either exposure to FC 113 (68.2 +/- 12.6 ppm) or trichloroethylene (8.9 +/- 3.1 ppm) during the application of these solvents in a cleaning procedure, whereas the control group (n = 7-11) was composed of non-solvent-exposed office workers in the same company. The initial investigation involved exposure to FC 113 while a follow-up study was undertaken after changes in work practices were made including replacement of FC 113 with trichloroethylene (TRI).

METHODS

Standard liver function tests and individual serum bile acids (ISBA) were measured before and after exposure to solvents and simultaneously in the control subjects by enzymatic methods and high performance liquid chromatography (HPLC), respectively.

RESULTS

Statistical analysis of the data showed a significant increase in the concentration of total serum bile acids (TSBA), some of the subgroups of SBA, and a few of the ISBA in workers after a period of exposure to FC 113. After TRI replaced FC 113 together with other changes in work practices to give substantial reduction in exposure to solvent, a repeat study also found elevated SBA after the cleaning procedure but to a lesser extent. No other indications of adverse liver effects, as measured by conventional parameters of hepatobiliary function, were detected.

CONCLUSION

Exposure to FC 113 was clearly associated with a significant rise in SBA levels, which are sensitive indicators of liver function. This finding is consistent with, and provides further support for, our previous investigations on chlorinated aliphatic hydrocarbon solvents which showed that SBA levels are a sensitive biological marker of exposure to these solvents. Changes in work practices including replacement of FC 113 resulted in a reduced effect on SBA, consistent with lower exposures.

Transcriptional activation and transformation by FosB protein require phosphorylation of the carboxyl-terminal activation domain

The transcription factor AP-1, composed of Fos-Jun dimers, mediates some aspects of the cellular response to growth factors. Transcriptional activation and neoplastic transformation by FosB, a member of the Fos family of proteins, require the presence of a potent C-terminal activation domain. Here we show by mutational analysis that the FosB C-terminal domain has a proline-based motif that is essential for both of these functions. Phosphopeptide mapping experiments show that the C terminus of FosB is phosphorylated within a cluster of functionally redundant serine residues that is adjacent to this proline-based motif. Mutation of these serine residues to alanine severely reduces the ability of this region to function as an activation domain and inhibits the ability of FosB protein to function as a transforming protein. Several observations suggest that the kinase responsible for phosphorylation of these sites is distinct from the mitogen-activation protein kinases and stress-activated protein kinases. Our results show that transcriptional activation and neoplastic transformation by the FosB protein are dependent on phosphorylation within the C terminus. This form of control may provide a potential mechanism of signal integration at the level of a single transcription factor.

Regulation of ApoE gene expression in mouse peritoneal macrophages by VLDL

Mouse peritoneal macrophages (MPM) were incubated with ApoE-poor VLDL or ApoE-rich VLDL at same concentrations for 24 h. The ApoE mRNA content increased in both groups than that in control and the highest ApoE mRNA content was seen in MPM incubated with ApoE-poor VLDL. The results suggest that VLDL could stimulate ApoE gene expression in MPM and the ApoE-poor VLDL has more pronounced effect. We think that the ApoE secreted by MPM may be incorporated into VLDL, especially the ApoE-poor VLDL, and thereby enhance the uptake of those lipoproteins by MPM or other local cells via ApoE-mediated receptor pathways.

[Study clinical application to determine heparin requirements during hemodialysis]

A de nove Weighted Stepwise Linear Model based on Gotch's heparin pharmacokinetic model has been designed to determine the heparin elimination rate constant during hemodialysis (HD). 100 times of HD in 26 patients with unstable dosage requirements of heparin were performed according to the computing method and the new heparin pharmacokinetic Weighted Stepwise Linear Model monitored be program of pocket calculator. The results showed not only stable anticoagulation but also successful prevention of patients's bleeding and avoidance of coagulation in hemodialyzer and blood tubing. The computer diagram presented in this paper is useful for propramming with different computer languages to calculate the heparin dosage requirements of patients undergoing HD.

Construction of eukaryotic expression vector pBlacz and its expression both in vitro and in vivo

A novel eukaryotic expression vector pBlacZ was constructed, which was transfected into the cell lines of NIH/3T3, COS-1, CHO and the primary culture of murine dermatic fibroblasts in vitro, and also into the murine subcutaneous layer and skeletal muscles of rats in vivo. It was detected that the gene expression vector could encode the E. Coli beta-galactosidase effectively in all these histocytes. The results suggested that pBlacZ, as a novel expression vector, might have certain value of application.

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.

Heat shock effects on phosphorylation of protein synthesis initiation factor proteins eIF-4E and eIF-2 alpha in Drosophila

Heat shock of mammalian cells causes changes in initiation factor phosphorylation that likely contribute to or cause the translation reprogramming characteristic of heat shock. In these investigations we have carried out a parallel analysis of Drosophila, focusing on eIF-4E and eIF-2 alpha. eIF-4E plus associated proteins was purified from lysates by m7GTP-Sepharose chromatography. A minor fraction (< 10%) of eIF-4E is phosphorylated under normal growth conditions, and phosphorylation decreases during heat shock. Drosophila eIF-2 alpha has been identified by in vitro translation of T7 RNA polymerase-transcribed mRNA, and immunoblotting with anti-Drosophila eIF-2 alpha antiserum. 32P-labeling analysis (unfractionated cell lysates and immunoprecipitates) detects phosphorylated eIF-2 alpha, whose amount increases approximately 2-3-fold upon heat shock. Immunoblotting analysis of two-dimensional gel-resolved proteins to determine the mass fraction of eIF-2 alpha phosphorylated detects a single eIF-2 alpha spot in both normal temperature and heat shocked cells, indicating less than 5% phosphorylation after and before heat shock. Staining quantification is consistent with this low prevalence. A major phosphoprotein which copurifies with eIF-4E on m7GTP-Sepharose shows decreased overall phosphorylation and decreased association with eIF-4E following heat shock. Several distinctive characteristics of this phosphoprotein suggest it is Drosophila eIF-4B.

Injecting drug use and HIV infection in southwest China

OBJECTIVES

To determine the prevalence of drug injection among drug users, the seroprevalence of HIV and risk factors for HIV infection among injecting drug users (IDU), and to determine heterosexual transmission of HIV among IDU and their spouses in southwest China.

METHODS

Using a cross-sectional design, we conducted an HIV seroprevalence and behavioral survey in three rural counties of Yunnan province, Ruili, Longchuan and Luxi in southwest China, bordering Myanmar (Burma). A total of 860 drug users were recruited in randomly selected communities at the three study sites (response rate, 97%). In addition, a random sample of 62 wives of HIV-infected IDU were assembled from 460 known HIV-positive IDU in Ruili and Longchuan (response rate, 81%).

RESULTS

In the sample of 860 drug users, 33% reported injecting drugs. Among the 282 subjects who injected drugs, 82% began intravenous drug use after 1988; 64% injected drugs at least once every day. All subjects shared needles but none cleaned the injection equipment with alcohol or bleach. Overall, 49% tested HIV-positive. HIV seropositivity was independently correlated with a longer history of drug injecting, daily injecting, frequent needle-sharing, being younger, and living in Ruili county. Among the 62 wives of HIV-positive IDU, none used condoms during sex and 10% tested HIV-positive.

CONCLUSIONS

We conclude that the introduction of HIV into drug-using communities and the rapid increase in heroin injecting in this population appear to have triggered an explosive HIV epidemic among IDU in southwest China. We recommend that AIDS prevention efforts should begin immediately and focus on discouraging the shift from opium smoking to heroin injecting, needle-sharing, and unprotected sex among drug users and their partners.

Isolation and characterization of the Drosophila melanogaster eIF-2 alpha gene encoding the alpha subunit of translation initiation factor eIF-2

Genomic and cDNA clones encoding the Drosophila melanogaster alpha-subunit of translational initiation factor 2 (eIF-2 alpha) were isolated. The D. melanogaster eIF-2 alpha gene encodes a 341 amino-acid (aa) protein that shares 57 and 44% identity to its human and yeast homologues, respectively. The regulatory phosphorylation site at Ser50 is embedded in a segment of 19 conserved aa residues. Analysis of the genomic DNA and cDNA clones indicated that eIF-2 alpha is a single-copy gene and its coding region is interrupted by a 260-bp intron. The D. melanogaster eIF-2 alpha mRNA is 1350 nt in length and is expressed throughout development.