Establishment and characterization of cell lines derived from uterine malignant mixed Müllerian tumor

OBJECTIVE

We report the establishment and characterization of three new cell lines derived from uterine malignant mixed müllerian tumor (MMMT).

METHODS

Three uterine MMMT cell lines from primary tumors of Korean patients were cultured and the involved cell morphology, growth properties, DNA profiles, immunohistochemical properties, tumor-associated antigen secretion, and genetic alterations of related oncogenes and tumor suppressor genes were studied as well.

RESULTS

Three MMMT cell lines were successfully established including one homologous tumor SNU-539 and two heterologous tumors SNU-685 and SNU-1077. All lines showed substrate adherence and high viability and were proven by DNA fingerprinting analysis to be unique. Contamination by mycoplasma and bacteria was excluded. SNU-539 and SNU-1077 cells stained positively for both epithelial and mesenchymal antigens, while SNU-685 cells only stained positively for mesenchymal antigens. The level of secretion of tumor-associated antigens, CA125 and CEA, was shown to be undetectable in all three lines. One missense mutation from AAC to GAC at codon 239 of exon 7 in the p53 gene was identified in SNU-539.

CONCLUSIONS

These newly established and characterized permanent uterine MMMT cell lines might be regarded as valuable resources for a multitude of in vitro investigations, which should be used for clarifying the obscure histogenetic origin and understanding the biological behavior of this aggressive tumor.

[Relative contribution of ageing and menopause to the changes of lumbar bone density in 1,400 Beijing women]

OBJECTIVE

To study the pattern of bone mass changes in women's lumbar spine and obtain evidence to guide the prevention of postmenopausal osteoporosis.

METHOD

Bone mineral content (BMC) and bone mineral density (BMD) of lumbar 1-4 in 1 400 Beijing women aged 20-85, were measured by dual energy X-ray absorptiometry.

RESULTS

(1) Both BMC and BMD increased after age 20, reached the peak at the age of 30, and decreased significantly after the age of 50; (2) There was no significant change of BMC and BMD after the age of 25 in premenopausal women. Bone loss accelerated in the first 10 years after menopause. Women who experienced menopause early had lower bone mass. (3) The prevalence of osteoporosis in 1 121 postmenopausal women was 17.40%.

CONCLUSION

Significant bone mass loss of lumbar spine occurs during the first decade following menopause, which is the key period for preventing osteoporosis.

[HPLC determination of diltiazem in human serum and its pharmacokinetic parameters]

A simple and sensitive reversed-phase liquid chromatographic method has been developed and validated for the analysis of diltiazem in human serum and the study of pharmacokinetics of the drug in human body. Diltiazem and diazepam (internal standard) in serum were extracted with hexane-chloroform-isopropanol (60:40:5, V/V), and then measured by HPLC using a Spherisorb C18 column as stationary phase and a methanol-water triethylamine as mobile phase. Diltiazem was quantified by ultraviolet absorbance at 239 nm. The method proved to be linear in the clinical range of 15-300 microg/L with a regression coefficient of 0.9997. The lower limit of detection of diltiazem in serum was 3 microg/L. Intra-day and inter-day coefficients of variation of assay for diltiazem in serum were 3.5%-6.8% (n=7) and 6.2%-8.4% (n=5), respectively. The recoveries of diltiazem were 91%-104% for serum. The method has been used to determine diltiazem in serum samples from eight volunteers and provided data on the pharmacokinetics of the drug. The results inferred that diltiazem is absorbed rapidly and had a relatively short half-life time in healthy individuals. The data obtained was fitted with PKBP-N1 program on computer to study the pharmacokinetics. The results showed that the peak level in serum averaged 118.5 microg/L +/- 14.3 microg/L at 3.1 h +/- 0.4 h, and the areas under the drug concentration curves (AUC) was 793.1 microg x h/L +/- 83.1 microg x h/L.

Establishment and characterization of human ovarian carcinoma cell lines

Five human ovarian carcinoma cell lines cultured from primary and metastatic tumors of Korean patients were characterized. These lines were isolated from two papillary serous cystadenocarcinomas, two endometrioid carcinomas, and one malignant Brenner tumor. It was shown that the growth of these cell lines was stable when cultured after at least 20 passages. Population doubling times varied from 40 to 67 hr. All lines showed high viability and were proven by DNA fingerprinting analysis to be unique. Contamination by mycoplasma or bacteria was excluded. In two lines, SNU-8 and SNU-840, an elevated level of CA125 antigen secretion could be detected, whereas CEA was undetectable in all five lines. Four different mutations in functional and highly conserved regions of the p53 gene were identified in three of our five lines (60%), namely in SNU-119, SNU-251, and SNU-563. Included were two missense mutations, one in-frame 3-base-pair deletion, and one out-of-frame 1-base-pair deletion. It is interesting to note that one of these three lines, SNU-251, presented an additional simultaneous nonsense mutation of the BRCA1 gene and missense mutation of the hMLH1 gene. In its lacking both wild-type alleles of the BRCA1 gene, SNU-251 might serve as an unusual and important in vitro model for studies related to ovarian carcinoma and the BRCA1 gene. It is thus likely that the establishment and characterization of these permanent human ovarian carcinoma cell lines in continuous cultures can provide useful tools for in vitro studies related to human ovarian carcinomas.

Calpain regulation of cytoskeletal signaling complexes in von Willebrand factor-stimulated platelets. Distinct roles for glycoprotein Ib-V-IX and glycoprotein IIb-IIIa (integrin alphaIIbbeta3) in von Willebrand factor-induced signal transduction

The adhesion of platelets to sites of vascular injury is critically dependent on the binding of subendothelial bound von Willebrand factor (vWf) to the platelet surface glycoprotein complexes, GP Ib-V-IX and GP IIb-IIIa (integrin alphaIIbbeta3). There is growing evidence that the binding of vWf to these receptors is not only essential for stable platelet adhesion but is also important for the transduction of activation signals required for changes in platelet morphology, granule secretion, and platelet aggregation. In this study we have investigated signaling events induced by vWf binding to GP Ib-V-IX in both spreading and aggregated platelets. The adhesion of platelets to vWf resulted in dramatic actin filament reorganization, as assessed by immunofluorescence with fluorescein isothiocyanate-conjugated phalloidin, and the cytoskeletal recruitment of various structural proteins (talin and integrin alphaIIbbeta3) and signaling enzymes (pp60c-src, focal adhesion kinase (FAK), phosphatidylinositol 3-kinase (PI 3-kinase), and protein-tyrosine phosphatase (PTP)-1B). Time course experiments in both spreading and aggregated platelets revealed that talin, FAK, and PTP-1B were proteolyzed after translocation to the cytoskeleton. The proteolysis of these proteins was dependent on the presence of extracellular calcium and was specifically inhibited by pretreating platelets with the membrane-permeable calpain inhibitors calpeptin, E64d, and MDL 28,170, but not with the membrane-impermeable inhibitors leupeptin, E64, and calpastatin. The cytoskeletal translocation of signaling enzymes in vWf-stimulated platelets was abolished by pretreating platelets with an anti-GP Ib-V-IX antibody but was unaffected by blocking ligand binding to integrin alphaIIbbeta3. In contrast, calpain activation in vWf-stimulated platelets required ligand binding to both GP Ib-V-IX and integrin alphaIIbbeta3. The activation of calpain in both spreading and aggregated platelets resulted in a substantial decrease in the level of tyrosine phosphorylation of multiple platelet proteins and was associated with a 50-80% reduction in the amount of cytoskeletal associated talin, integrin alphaIIbbeta3, PI 3-kinase, FAK, pp60(c-)src, and PTP-1B. These studies suggest a potentially important role for calpain in regulating the formation and/or stability of cytoskeletal signaling complexes in vWf-stimulated platelets. Furthermore, they demonstrate distinct roles for GP Ib-V-IX and integrin alphaIIbbeta3 in vWf-induced signal transduction.

[Effects of hypoxia on the release of PDGF-B chain from pulmonary artery endothelial cells and on growth of pulmonary artery smooth muscle cells]

Platelet-derived growth factor (PDGF), content in hypoxic endothelial cells conditioned medium (HECCM) and normoxic endothelial cells conditioned medium (NECM) was determined using protein dot blot assay. The effects of HECCM and NECCM on the growth of pulmonary artery smooth muscle cells (PASMC) were assessed with [3H]-thymidine incorporation technique and flow cytometric analysis. PDGF content in HECCM was higher than that in NECCM. HECCM dramatically enhanced the DNA synthesis in PASMC and significantly promoted the cell cycle progression of PASMC from G0/G1 phase to S phase. In addition, administration of anti-PDGF-B chain monoclonal antibodies blocked markedly the DNA synthesis of PASMC stimulated by HECCM and obviously inhibited the entry of the cells from G0/G1 phase to S phase. These results suggest that increased PDGF release from pulmonary artery endothelial cells under hypoxia could stimulate the proliferation of PASMC which may induce pulmonary vascular reconstruction and involve in the development of hypoxic pulmonary hypertension.

[Total knee replacement in diabetic patients]

From December 1987 to March 1995, 16 TKRs were performed for 9 diabetic patients at our department. 7 of them had rheumatoid arthritis (RA), and 2 osteoarthritis (OA). There were 1 male and 8 females. The average age was 55.9 years (range 49-69 years), and the average weight was 64.5 kg (range 54-78 kg). According to the hospital for special surgery (HSS) knee rating scale, the pre and postoperative evaluations were made. The HSS scores were improved after the operation from average 30.2 points preoperatively to 78.2 points postoperatively. The excellent and good rate was 94%. After 3.9 years follow-up (range 10 months to 8 years), the HSS score was 74.4 points, and the rate of excellent and good was 87.5%. Compared to the other 209 RA or OA patients with 287 TKR at the same period, the HSS score was almost the same, but the infection rate was higher (3.5%). We conclude that the TKR of diabetic patients could also get the similar results as common patients if the patients are under the good control of glycemia and medical treatment.

[Prognosis prediction of S-phase fraction and p53, c-erbB-2, estrogen receptor, progesterone receptor in axillary node-negative breast cancer]

The prognostic factors in 180 axillary node-negative breast cancer patients with more than 5 year follow-up were searched for with multiple regression. Based on the regression results, the cases with treatment failure in 5 year and the cases with 5 year disease free survival were matched at 1:2 ratio. Then the c-erbB-2 protein, p53 Protein, estrogen receptor (ER), progesterone receptor (PR) and the S-phase fraction (SPF) were measured in paraffin-embedded breast cancer tissue. The results were analysed with log-rank test and Cox-Model. Among the biobehaviour factors measured, the SPF was the strongest prognosis predictor for ANN. The 5 year disease free survival rate of ANN with SPF < 10% or > 10% was 94% and 52% respectively (P < 0.001). The treatment failure relative risk of patients with SPF > 10% ANN was 11.31. The relative risk of other four factors was respectively, PR 3.58 (P < 0.002), ER 2.93 (P < 0.05), p53 1.44 (P > 0.3), c-erbB-2 1.38 (P > 0.5). The combination of PR or EP with SPF could make the relative risk even higher.

Action of methylmercury on GABA(A) receptor-mediated inhibitory synaptic transmission is primarily responsible for its early stimulatory effects on hippocampal CA1 excitatory synaptic transmission

Bath application of methylmercury (MeHg) causes an early stimulation before block of synaptic transmission in the CA1 region of hippocampal slices. Effects of MeHg and Hg++ on inhibitory postsynaptic potentials (IPSPs) or currents (IPSCs) and excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) were compared to test whether or not early block by MeHg of GABA(A)-mediated inhibitory synaptic transmission and MeHg-induced alterations of the resting membrane potentials of CA1 neurons contribute to this initial enhancement of excitability. MeHg affected IPSPs and IPSCs similarly, and more rapidly than EPSPs and EPSCs. In contrast, although Hg++ blocked IPSPs more rapidly than EPSPs, times to block of IPSCs and EPSCs by Hg++ were virtually identical when CA1 neurons were voltage-clamped at their resting membrane potential levels. MeHg increased EPSC amplitudes before their subsequent decrease even when CA1 neuronal membranes were voltage-clamped at their resting potentials. This suggests that effects of MeHg on CA1 cell membrane potentials are not a major factor for MeHg-induced early stimulation of hippocampal synaptic transmission. Effects of MeHg and Hg++ on the reversal potentials for IPSCs also differed. Both metals blocked all outward and inward currents generated at different holding potentials. However, MeHg shifted the current-voltage (I/V) relationship to more positive potentials, although Hg++ shifted the I/V curve to more negative potentials. Hg++ was a less potent blocker of on IPSCs and EPSPs or EPSCs than was MeHg. To determine if the early increase in amplitude of population spikes or EPSPs is due to an action of MeHg at GABA(A) receptors, extracellular recordings of population spikes and intracellular recordings of EPSPs were compared with or without pretreatment of hippocampal slices with bicuculline. After preincubation of slices with 10 microM bicuculline for 30 to 60 min, MeHg only decreased the amplitudes of population spikes and EPSPs to block; no early increase of synaptic transmission occurred. Pretreatment of slices with strychnine, did not prevent MeHg-induced early increase in population spikes. MeHg also blocked responses evoked by bath application of muscimol, a GABA(A) agonist. Thus, block by MeHg of GABA(A) receptor-mediated inhibitory synaptic transmission may result in disinhibition of excitatory hippocampal synaptic transmission, and appears to be primarily responsible for the initial excitatory effect of MeHg on hippocampal synaptic transmission.

[The reversion of multidrug resistance in tumour cell line MCF-7/Adr by ribozyme]

OBJECTIVE

To construct a specific hammerhead ribozyme possessing catalytic activity that cleaves the mdr1 mRNA for reversing the resistant phenotype in tumour cell line.

METHODS

A DNA sequence encoding the ribozyme gene was incorporated into a eukaryotic expression vector (pH beta Apr-1 neu) and transfected into the human breast carcinoma cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype.

RESULTS

The ribozyme was stably expressed in the cell line, and decreased the level of mdr1 mRNA expression by 83.5%. The ribozyme inhibited the formation of P-glycoprotein and reduced the cell's resistance to adriamycin.

CONCLUSION

The resistant cells were 1,000-fold more resistant than the parental cell line (MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line.

MMAS-1, the branch point between cis- and trans-cyclopropane-containing oxygenated mycolates in Mycobacterium tuberculosis

The proportion of mycolic acid containing trans-substituents at the proximal position of the meromycolate chain is an important determinant of fluidity of the mycobacterial cell wall and is directly related to the sensitivity of mycobacterial species to hydrophobic antibiotics. MMAS-1, an enzyme encoded in the gene cluster responsible for the biosynthesis of methoxymycolates, was overexpressed in Mycobacterium tuberculosis and shown to result in the overproduction of trans-cyclopropane and trans-olefin-containing oxygenated mycolic acids. MMAS-1 converted a cis-olefin into a trans-olefin with concomitant introduction of an allylic methyl branch in a precursor to both the methoxy and ketone-containing mycolic acids. In addition to an increase in the amount of trans-mycolate, MMAS-1 expression resulted in a substantial increase in the amount of ketomycolate produced relative to methoxymycolate. Thus MMAS-1 may act at a complex branch point where expression of this enzyme directly affects the cis- to trans-ratio and indirectly affects the keto to methoxy ratio. Overexpression of MMAS-1 resulted in a substantially slower growth rate at moderately elevated temperature, decreased thermal stability of the cell wall as measured by differential scanning calorimetry, and an increased permeability to chenodeoxycholate. These results provide experimental evidence for the intermediacy of trans-olefinic mycolate precursors in trans-cyclopropane formation and suggest that increasing the proportion of the polar ketomycolate subclass may exert a significant fluidizing effect on the cell wall.

Adverse reactions to food constituents: allergy, intolerance, and autoimmunity

Food allergies and intolerance represent important health concerns to consumers who are predisposed to these illnesses. Unlike many current food safety issues, food sensitivities are complicated by both complex and multiple individual adverse reactions, which can vary from emotional to pathophysiological ailments. In some instances, the underlying mechanisms that result in the development of food allergies or intolerance have marked differences but produce common symptoms. The present-day diagnosis of these disorders can be impeded by intrinsic limitations in generating accurate information from patient history and biochemical, physicochemical, and immunochemical tests. Oral challenge tests represent effective methods for confirming and testing food allergens and food intolerance; however, these procedures are often restricted to clinical trials. It is important to be able to distinguish among food allergy, intolerance, and autoimmune disease in the management of these disorders. The role of food in the development of autoimmune disease may be exemplified by celiac disease, a food-induced enteropathy, requiring exposure to prolamins in wheat, rye, and barley. Various wheat and soy protein sources, including the soy protein isolates used to make infant formulas, have been related to juvenile or insulin-dependent diabetes mellitus (IDDM), a common chronic disease of childhood. Employing food process technologies to eliminate food constituents with potential for intolerance in some individuals is a potentially viable approach for reducing risk to food-related disorders. Finally, the development of food labelling regulations that require the identification of potential food allergens or agents for intolerance in the ingredient declaration on prepackaged food is a positive step toward the prevention of severe adverse reactions in hypersensitive individuals.

Myosin light chain phosphorylation: modulation of basal and agonist-stimulated venular permeability

We have previously demonstrated that agonists increase microvascular permeability through a phospholipase C-nitric oxide synthase-guanylate cyclase cascade. The aim of this study was to further investigate the downstream end of the signaling pathway with a focus on myosin light chain (MLC) phosphorylation. The apparent permeability coefficient to albumin was measured in isolated coronary venules. Under control conditions, the nitric oxide donor sodium nitroprusside, as well as the guanosine 3',5'-cyclic monophosphate-dependent protein kinase (PKG) activator 8-bromoguanosine 3',5'-cyclic monophosphate, increased venular permeability two- to threefold. Similarly, activation of protein kinase C (PKC) with phorbol 12-myristate 13-acetate significantly elevated permeability. Inhibition of MLC phosphorylation with ML-7 significantly attenuated the hyperpermeability responses to the agonists. Furthermore, ML-7 dose dependently reduced basal venular permeability. Consistently, inhibition of dephosphorylation with the protein phosphatase inhibitor calyculin dramatically increased basal permeability. These results suggest that 1) PKG and PKC play an important signaling role in the regulation of endothelial barrier function and 2) MLC phosphorylation contributes to basal and agonist-stimulated microvascular permeability.

[Effect of methylphenidatum on inspiratory muscles function in patients with chronic obstructive pulmonary disease and its mechanism]

To have a better understanding of the effect of methylphenidatum on inspiratory muscles function, we studied the respiratory force parameters of 70 patients with chronic obstructive pulmonary disease by intravenous infusion methylphenidatum in a randomized controlled clinical trial. The indices of respiratory force parameter included maximal inspiratory mouth pressure (MIP), maximal midinspiratory flow (MMIF), forced inspiratory capacity (FIC), maximal works of inspiration (Wimax) and airway occlusion pressure (P0.1), etc. Aminophylline and Nikethamidi were chosen as controls. The results showed that MIP, MMIF, FIC, Wimax, P0.1 and minute ventilation (Vr) were significantly increased after administration of methylphenidatum and aminophylline. There were no significant differences in MIP, MMIF, FIC and Wimax after administration of Nikethamidi, but P0.1 was significantly increased and the increase was higher than that after administration of methylphenidatum and aminophylline groups. We conclude that methylphenidatum can significantly improve the function of inspiratory muscles as aminophylline can do.

Solitary Langerhans cell histiocytosis lesion of the parieto-occipital lobe: a case report and review of the literature

A 38 year-old woman with a solitary intracerebral Langerhans cell histocytosis (LCH) lesion is presented, in whom, cerebral magnetic resonance imaging (MRI) revealed a non-enhancing mass in the right parieto-occipital lobe. The surgical specimen consisted of a nodular polymorphic infiltrate of mononuclear histiocytic cells, macrophages, eosinophilic granulocytes, lymphocytes and Langerhans giant cells involving leptomeninges, cerebral cortex and white matter. The histiocytes displayed features of Langerhans cells such as CD1a and S-100 immunopositivity, and of reticulum cells such as Ki-M4P and X-12 immunopositivity. This case as well as ten other cases from the literature are reviewed.

Calpain cleavage of focal adhesion proteins regulates the cytoskeletal attachment of integrin alphaIIbbeta3 (platelet glycoprotein IIb/IIIa) and the cellular retraction of fibrin clots

The intracellular thiol protease calpain catalyzes the limited proteolysis of various focal adhesion structural proteins and signaling enzymes in adherent cells. In human platelets, calpain activation is dependent on fibrinogen binding to integrin alphaIIbbeta3 and subsequent platelet aggregation, suggesting a potential role for this protease in the regulation of postaggregation responses. In this study, we have examined the effects of calpain activation on several postaggregation events in human platelets, including the cytoskeletal attachment of integrin alphaIIbbeta3, the tyrosine phosphorylation of cytoskeletal proteins, and the cellular retraction of fibrin clots. We demonstrate that calpain activation in either washed platelets or platelet-rich plasma is associated with a marked reduction in platelet-mediated fibrin clot retraction. This relaxation of clot retraction was observed in both thrombin and ionophore A23187-stimulated platelets. Calcium dose-response studies (extracellular calcium concentrations between 0.1 microM and 1 M) revealed a strong correlation between calpain activation and relaxed clot retraction. Furthermore, pretreating platelets with the calpain inhibitors calpeptin and calpain inhibitor I prevented the calpain-mediated reduction in clot retraction. Relaxed fibrin clot retraction was associated with the cleavage of several platelet focal adhesion structural proteins and signaling enzymes, resulting in the dissociation of talin, pp60(c-)src, and integrin alphaIIbbeta3 from the contractile cytoskeleton and the tyrosine dephosphorylation of multiple cytoskeletal proteins. These studies suggest an important role for calpain in the regulation of multiple postaggregation events in human platelets. The ability of calpain to inhibit clot retraction is likely to be due to the cleavage of both structural and signaling proteins involved in modulating integrin-cytoskeletal interactions.

[Immunologically prepared plasma specimen of albuterol for high performance liquid chromatographic determination]

Immune-affinity method for preparation of sample in plasma is reported in this paper. Albuterol was coupled to bovine serum albumin (BSA) to prepare the antigen and immunized in rabbit to produce the anti-albuterol serum (immune globulin). The anti-albuterol serum was treated with saturated ammonium sulfate solution to obtain the antibody (immune globulin). The antibody was coupled with Sepharose 4B to prepare the immune globulin-affinity column. The plasma containing albuterol was introduced into the column and was rinsed in turn with phosphate buffer and water, and then eluted with methanol. After being concenfrated the sample was analyzed by HPLC with a sillica column (4.6 mm x 200 mm, 5 microm), a mixture of methanol: 2 mol/L ammonium acetate (99.5 : 0.5) as mobile phase with a flow rate of 1.2 mL/min, and fluorecence detector monitoring at lambdaex = 226 nm and lambdaem = 306 nm. The results showed that the immune globulin-affinity column has the characteristic of high purity and high specificity, and it is suitable for the preparation of chromatographic plasma specimen to determine albuterol in plasma. The relationship between peak area ratios and concentration from 2 to 80 microg/L were linear (r=0.998). The extraction recoveries from plasma at concentrations of 2-80 microg/L were 98.8% +/- 7.3%. The RSD for intra-day (n=5) was 5.8% and that for inter-day assay (n=5) was 7.8%.

Preliminary studies on the relationship between autoantibodies to heat stress proteins and heat injury of pilots during acute heat stress

Comparison in the heart rate, oral temperature and lymphocyte DNA damage during heat stress was made in pilots with negative antibodies to heat stress proteins (HSPs) and those with positive antibodies in the man-made climate room with Western blot and comet assay. Our results showed that the increase in oral temperature, heart rate and lymphocyte DNA damage in pilots with the positive antibodies to HSPs were higher than those in pilots with the negative antibodies during heat stress. These results indicated that the presence of autoantibodies in plasma of pilots might reflect heat damage and high sensitivity to heat.

[Cetirizine improves the resistance of airway and pulmonary function in patients with asthma]

The objective of this study was to investigate the possible anti-asthma role of Cetirizine. Forty asthmatics were randomly divided into two groups. The experimental group had 30 patients. Among them were 10 patients with simple asthma, 5 patients complicated by mild emphysema, 6 patients complicated by moderate emphysema and 9 patients complicated by severe emphysema. Vit-C (control) group had 10 cases, including 2 cases of simple asthma, 6 cases complicated by mild emphysema and 2 cases complicated by moderate emphysema. All patients had a single oral dose of 5 mg Cetirizine or 0.1 g Vit-C blindly. Before and 0.5, 1 hour after their medicines, the resistance of airway (Raw), sGaw and MEFV were examined in all patients on 6200 Plethysmograph. The measured values showed a significant improvement of Raw and sGaw after administration of Cetirizine. In half an hour after Cetirizine, the Raw decreased by 20.408%, and sGaw increased by 28.249%. In one hour after Cetirizine, Raw further decreased by 24.34% and sGaw increased by 41.153% (P < 0.001). The FVC in MEFV increased by 4.96% (P < 0.02) in one hour after Cetirizine, but other parameters in MEFV curve (PEF, FEV1, MMEF) had no significant changes. All parameters in control group had no significant changes (P > 0.05). The results indicate that Cetirizine could decrease Raw in asthmatics, improve their lung ventilatory function. Cetirizine is a new H-receptor antagonist usually used as anti-inflammatory and allergy suppression medication. It is shown that Cetirizine is a promising anti-asthma agent in treating bronchial asthma.

VEGF induces NO-dependent hyperpermeability in coronary venules

The purpose of this study was to investigate the direct effect of vascular endothelial growth factor (VEGF) on microvascular permeability and its signaling mechanisms. The apparent permeability coefficient to albumin was measured in isolated coronary venules. Topical application of VEGF dose-dependently and transiently increased albumin permeability by two- to threefold. Inhibition of nitric oxide (NO) synthesis with NG-monomethyl-L-arginine abolished VEGF-induced venular hyperpermeability. Furthermore, because NO exerts vasoactive effects through stimulation of guanylate cyclase (GC) and the subsequent production of guanosine 3',5'-cyclic monophosphate (cGMP), we examined the role of GC and cGMP-dependent protein kinase (PKG) in the mediation of VEGF's action. The permeability response to VEGF was measured in the presence of the selective GC inhibitor 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one and the specific PKG inhibitor KT-5823. Both inhibitors reduced basal permeability and prevented the hyperpermeability response to VEGF. Therefore, we suggest that VEGF modulates microvascular permeability via a signaling cascade involving NO synthesis, GC stimulation, and PKG activation.

A common mechanism for the biosynthesis of methoxy and cyclopropyl mycolic acids in Mycobacterium tuberculosis

Mycobacterium tuberculosis produces three classes of mycolic acids that differ primarily in the presence and nature of oxygen-containing substituents in the distal portion of the meromycolate branch. The methoxymycolate series has a methoxy group adjacent to a methyl branch, in addition to a cyclopropane in the proximal position. Using the gene for the enzyme that introduces the distal cyclopropane (cma1) as a probe, we have cloned and sequenced a cluster of genes coding for four highly homologous methyl transferases (mma1-4). When introduced into Mycobacterium smegmatis, this gene cluster conferred the ability to synthesize methoxymycolates. By determining the structure of the mycolic acids produced following expression of each of these genes individually and in combination, we have elucidated the biosynthetic steps responsible for the production of the major series of methoxymycolates. The mma4 gene product (MMAS-4) catalyzes an unusual S-adenosyl-L-methionine-dependent transformation of the distal cis-olefin into a secondary alcohol with an adjacent methyl branch. MMAS-3 O-methylates this secondary alcohol to form the corresponding methyl ether, and MMAS-2 introduces a cis-cyclopropane in the proximal position of the methoxy series. The similarity of these reactions and the enzymes that catalyze them suggests that some of the structural diversity of mycolic acids results from different chemical fates of a common cationic intermediate, which in turn results from methyl group addition to an olefinic mycolate precursor.

Non-receptor protein tyrosine kinases and phosphatases in human platelets

There is now a large and rapidly growing body of information on the different types of non-receptor tyrosine kinases and phosphatases present within platelets. These enzymes appear to play a critical role in co-ordinating, integrating and amplifying signals from multiple cell surface receptors. Despite considerable progress in this area of research over the last decade, a coherent understanding of how these enzymes fit into the complex communication networks of platelets remains elusive. The challenge ahead will be to define the molecular interactions and hierarchies between tyrosine kinases, phosphatases and other platelet signalling enzymes, and to pinpoint the key phosphorylation reactions required for the induction of specific platelet responses.

[A study on plasma non-species specific antibody in employees working in a automobile engine testing workshop]

To investigate the existence of the non-species specific antibody in plasma of the employees working in an automobile engine testing workshop, and to use it as a scanning marker of various hazards, the heat-stress protein antigen method and western blot technique were used. This study showed that employees working in the automoblile engine testing workshop were affected by various hazards, such as noise, toxic chemicals (carbon monoxide, lead fume, benzene, and so on), and there existed non-species specific antibodies against protein 103,900 and 54,200 of rat liver in their plasma, which were postulated as the specific products produced by exposure to occupational hazards, such as noise, carbon monoxide, et al.

The bioactive phospholipid, lysophosphatidylcholine, induces cellular effects via G-protein-dependent activation of adenylyl cyclase

The naturally occurring phospholipid, lysophosphatidylcholine (lyso-PC), regulates a broad range of cell processes, including gene transcription, mitogenesis, monocyte chemotaxis, smooth muscle relaxation, and platelet activation. Despite the growing list of cellular effects attributable to lyso-PC, the mechanism(s) by which it alters cell function have not been elucidated. In this report, we have examined the effects of exogenous lyso-PC on signal transduction processes within a variety of lyso-PC-responsive cells, including human platelets, monocyte-like THP-1 cells, and the megakaryoblastic cell line, MEG-01. Pretreatment of each of these cells with increasing concentrations of lyso-PC (25-150 microg/ml) was associated with a progressive increase in the cytosolic concentration of cAMP. The accumulation of cAMP in platelets correlated closely with the ability of lyso-PC to inhibit multiple platelet processes, including platelet aggregation, agonist-induced protein kinase C activation, thromboxane A2 generation, and the tyrosine phosphorylation of platelet proteins. In each of the cell types examined, the ability of lyso-PC to increase the cellular levels of cAMP was synergistically enhanced by pretreating the cells with the cAMP phosphodiesterase inhibitor, theophylline (5 mM), and was specifically inhibited by the P-site inhibitor of adenylyl cyclase, 2,5-dideoxyadenosine. A role for the stimulatory G-protein, Gs, in the lyso-PC-induced activation of adenylyl cyclase was suggested by the ability of the GTPase inhibitor, guanylyl 5'-thiophosphate (0.2 mM), to inhibit the lyso-PC-stimulated increase in cAMP, and also by the ability of cholera toxin to inhibit increases in membrane GTPase activity in response to lyso-PC. The functional significance of lyso-PC-induced activation of adenylyl cyclase was investigated in MEG-01 cells. Treatment of these cells with either lyso-PC or dibutyryl cAMP for 36-40 h resulted in a 3-5-fold increase in the surface expression of the natural anticoagulant protein, thrombomodulin (TM). The ability of lyso-PC to increase TM expression was abolished by pretreating these cells with the adenylyl cyclase inhibitor, 2,5-dideoxyadenosine, whereas the dibutyryl cAMP-induced increase in TM remained insensitive to adenylyl cyclase inhibition. These studies define an important role for the adenylyl cyclase signaling system in mediating cellular effects induced by lyso-PC.