Molecular aptamer for real-time oncoprotein platelet-derived growth factor monitoring by fluorescence anisotropy

Monitoring proteins in real time and in homogeneous solution has always been a difficult task. We have applied a fluorophore-labeled molecular probe based on a high-affinity platelet-derived growth factor (PDGF) aptamer for the ultrasensitive detection of PDGF in homogeneous solutions. The aptamer is labeled with fluorescein to specifically bind with the PDGF protein. Fluorescence anisotropy is used for the real-time monitoring of the binding between the aptamer and the protein. When the labeled aptamer is bound with its target protein, the rotational motion of the fluorophore attached to the complex becomes much slower because of an increased molecular weight after binding, resulting in a significant fluorescence anisotropy change. Using the anisotropy change, we are able to detect the binding events between the aptamer and the protein in real time and in homogeneous solutions (detection without separation). This assay is highly selective and ultrasensitive. It can detect PDGF in the subnanomolar range. The new method for protein detection is simple and inherits all of the advantages of molecular aptamers. Efficient oncoprotein detection using aptamer-based fluorescence anisotropy measurement will find wide applications in protein monitoring, in cancer diagnosis as well as other studies in which protein analysis is important.

Novel erythromycin derivatives with aryl groups tethered to the C-6 position are potent protein synthesis inhibitors and active against multidrug-resistant respiratory pathogens

A novel series of erythromycin derivatives has been discovered with potent activity against key respiratory pathogens, including those resistant to erythromycin. These compounds are characterized by having an aryl group tethered to the C-6 position of the erythronolide skeleton. Extensive structural modification of the C-6 moiety led to the discovery of several promising compounds with potent activity against both mef- and erm-mediated resistant Streptoccoccus pneumoniae. Preliminary mechanistic studies indicated that the new macrolides are potent protein synthesis inhibitors, which interact with methylated ribosomes isolated from resistant organisms. In experimental animal models, these compounds exhibited excellent in vivo efficacy and balanced pharmacokinetic profiles.

Effects and mechanisms of H(2)O(2) on production of dicarboxylic acid

The system of producing long chain dicarboxylic acid (DCA) by Candida tropicalis is an aerobic and viscous fermentation system. A method to overcome the gas-liquid transport resistance and to increase oxygen supply is by adding hydrogen peroxide (H(2)O(2)) to the fermentation system. Here we report that the H(2)O(2) not only can enhance the oxygen supply but also change the metabolism by inducing cytochrome P450, the key enzyme of a, o-oxidation. When C. tropicalis was cultivated in a 3-L bioreactor using the combination of aeration and H(2)O(2) feeding, DCA production rates increased by about 10% after a short period of decrease at the beginning. Furthermore, the experiments showed that the maximum activities of P450 could be induced at 2 mM H(2)O(2), and the inducible mechanisms are also discussed. Moreover, we suggest that alkane might be oxidized through the "peroxide shunt pathway" when H(2)O(2) is present. By adding H(2)O(2), the DCA yield in a 22-L bioreactor could increase by 25.3% and reach 153.9 g/L.

A naturally occurring non-coding fusion transcript derived from scorpion venom gland: implication for the regulation of scorpion toxin gene expression

Scorpion venom glands synthesize and secrete a great number of low molecular mass toxic peptides for prey and defense. Many cDNAs and genomic genes encoding these toxins have been isolated and sequenced. However, their expression regulation mechanism is not yet known at present. During screening of a cDNA library prepared from venom glands of the scorpion Buthus martensii Karsch, we isolated a natural fusion cDNA composed of the 5'-untranslated region (UTR) and upstream coding sequence of a long-chain toxin transcript and the downstream coding sequence and 3'-UTR of a short-chain toxin transcript. The junction site is just the overlapping region of 11 nucleotides (GGCAAGGAAAT) between the two wild transcripts, and thus leads to the formation of an early stop codon, which will cause premature translation. Based on the above observations, combined with the genomic data, we proposed a characteristic regulation mechanism of scorpion toxin genes, in which trans-splicing and nonsense mediated mRNA decay are involved.

Kruppel-like factor 4 regulates laminin alpha 3A expression in mammary epithelial cells

Laminin-5, the major extracellular matrix protein produced by mammary epithelial cells, is composed of three chains (designated alpha3A, beta3, and gamma2), each encoded by a separate gene. Laminin-5 is markedly down-regulated in breast cancer cells. Little is known about the regulation of laminin gene transcription in normal breast cells, nor about the mechanism underlying the down-regulation seen in cancer. In the present study, we cloned the promoter of the gene for the human laminin alpha3A chain (LAMA3A) and investigated its regulation in functionally normal MCF10A breast epithelial cells and several breast cancer cell lines. Using site-directed mutagenesis of promoter-reporter constructs in transient transfection assays in MCF10A cells, we find that two binding sites for Kruppel-like factor 4 (KLF4/GKLF/EZF) are required for expression driven by the LAMA3A promoter. Electrophoretic mobility shift assays reveal absence of KLF4 binding activity in extracts from T47D, MDA-MB 231, ZR75-1, MDA-MB 436, and MCF7 breast cancer cells. Transient transfection of a plasmid expressing KLF4 activates transcription from the LAMA3A promoter in breast cancer cells. A reporter vector containing duplicate KLF4-binding sites in its promoter is expressed at high levels in MCF10A cells but at negligible levels in breast cancer cells. Thus, KLF4 is required for LAMA3A expression and absence of laminin alpha3A in breast cancer cells appears, at least in part, attributable to the lack of KLF4 activity.

Role of angiotensin II in tubulointerstitial injury

The renin angiotensin system (RAS) has been implicated in tubulointerstitial injury in a range of clinical and experimental settings. Angiotensin II, the major effector molecule of the RAS, in addition to its effects on systemic blood pressure and intrarenal hemodynamics, also acts as a local hormone and growth factor to modulate renal function and pathology. There is increasing evidence for a pivotal role of this hormone in influencing renal tubular and interstitial function and structure including regulation of multiple cytokines and chemokines, promoting infiltration of monocytes/macrophages, promoting cellular proliferation, and inducing apoptosis. Pathologic actions of angiotensin II lead to tubulointerstitial fibrosis and inflammation via a range of cytokines and chemokines including transforming growth factor (TNF)-beta1, osteopontin, tumor necrosis factor (TNF)-alpha, secreted protein acidic and rich in cysteine (SPARC), and RANTES (regulated on activation normal T-cell expression and secreted). Blockade of production of angiotensin II by an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor antagonism with an angiotensin type 1 receptor antagonist has been shown to attenuate tubulointerstitial injury and reduce expression of cytokines and matrix proteins. The role of angiotensin II in tubulointerstitial fibrosis and inflammation is addressed in this article.

Mitochondrial DNA deletion mutations are concomitant with ragged red regions of individual, aged muscle fibers: analysis by laser-capture microdissection

Laser-capture microdissection was coupled with PCR to define the mitochondrial genotype of aged muscle fibers exhibiting mitochondrial enzymatic abnormalities. These electron transport system (ETS) abnormalities accumulate with age, are localized segmentally along muscle fibers, are associated with fiber atrophy and may contribute to age-related fiber loss. DNA extracted from single, 10 microm thick, ETS abnormal muscle fibers, as well as sections from normal fibers, served as templates for PCR-based deletion analysis. Large mitochondrial (mt) DNA deletion mutations (4.4-9.7 kb) were detected in all 29 ETS abnormal fibers analyzed. Deleted mtDNA genomes were detected only in the regions of the fibers with ETS abnormalities; adjacent phenotypically normal portions of the same fiber contained wild-type mtDNA. In addition, identical mtDNA deletion mutations were found within different sections of the same abnormal region. These findings demonstrate that large deletion mutations are associated with ETS abnormalities in aged rat muscle and that, within a fiber, deletion mutations are clonal. The displacement of wild-type mtDNAs with mutant mtDNAs results in concomitant mitochondrial enzymatic abnormalities, fiber atrophy and fiber breakage.

Crystallization and preliminary X-ray crystallographic analysis of native and selenomethionyl recombinant tabtoxin-resistance protein complexed with acetyl-coenzyme A

Tabtoxin-resistance protein (TTR), an acetyltransferase from Pseudomonas syringae pv. tabaci, was overexpressed in Eschericha coli M15 and the TTR fusion protein complexed with acetyl-coenzyme A (AcCoA) was purified and crystallized. Diffraction data were collected to 3.0 A resolution in-house and the crystal was found to belong to space group P2(1), with unit-cell parameters a = 47.6, b = 66.6, c = 53.5 A, beta = 104.3 degrees. Furthermore, a selenomethionine (SeMet) TTR fusion protein derivative was overexpressed in the same expression system and its complex with AcCoA was purified in a reductive environment. The SeMet TTR derivative crystallized in two forms: the first was identical to that observed for native crystals and the second belonged to space group C2, with unit-cell parameters a = 101.7, b = 45.6, c = 84.2 A, beta = 105.8 degrees. Data from the P2(1) crystal form were collected in-house to 2.3 A resolution. Subsequently, three different wavelength data sets of the C2 crystal form to 1.55 A resolution were collected at the Advanced Photon Source at Argonne National Laboratory.

Phase shift at a turning point in a planar optical waveguide

We present a novel matrix approach to proving that the phase shift at a turning point in a planar optical wave-guide is exactly equal to pi rather than to pi/2 or to some other value. We also show the existence of phase contributions from reflected subwaves, which to our knowledge have never been taken into account previously.

[The progress of electrogastrogram]

This paper reviews the advances in basic researches on the physiological factors and other factors that influence electrogastrogram and summarizes the clinical application of electrogastrogram in the diagnoses and studies of gastric dyspepsia, gastroparesis, delayed gastric emptying, kinetia and gastrohelcosis.

Homologs of gp91phox: cloning and tissue expression of Nox3, Nox4, and Nox5

gp91phox is the catalytic subunit of the respiratory burst oxidase, an NADPH-dependent, superoxide generating enzyme present in phagocytes. In phagocytes, the enzyme functions in host defense, but reactive oxygen generation has also been described in a variety of non-phagocytic cells, including cancer cells. We previously reported the cloning of Nox1 (NADPH oxidase1), a homolog of gp91phox, its expression in colon and vascular smooth muscle, and its oncogenic properties when overexpressed [Suh et al. (1999). Nature 401, 79-82]. Herein, we report the cloning and tissue expression of three additional homologs of gp91phox, termed Nox3, Nox4 and Nox5, members of a growing family of gp91phox homologs. All are predicted to encode proteins of around 65 kDa, and like gp91phox, all show 5-6 conserved predicted transmembrane alpha-helices containing putative heme binding regions as well as a flavoprotein homology domain containing predicted binding sites for both FAD and NADPH. Nox3 is expressed primarily in fetal tissues, and Nox4 is expressed in not only fetal tissues, but also kidney, placenta and glioblastoma cells. Nox5 is expressed in a variety of fetal tissues as well as in adult spleen and uterus. Nox isoforms are aberrantly expressed in several cells derived from human cancers, with Nox4 being the isoform most frequently expressed in the tumor cells investigated. Thus, expression of Nox family members is likely to account for some of the reactive oxygen generation seen in non-phagocytic cells.

[Relationships between soil-plant nutrition, quality of agricultural products and human and livestock health]

The abundant and insufficient situation of essential elements such as calcium magnesium, sulphur, zinc and iron and beneficial elements such as selenium and iodine in soils was reviewed, and the influences of these elements and organic matter on the quality of agricultural products and human and livestock health were discussed. The trends of future research in the field of soil element science and plant nutrition, in particular, the quality of agricultural products were prospected.

Modified labial tissue sliding flaps for repairing large lower lip defects

PURPOSE

Common flap techniques for reconstructing large defects in the lower lip are often destructive and complex and result in unsatisfactory function and appearance. This article describes a modified technique that uses sliding labial tissue flaps to avoid these problems.

PATIENTS AND METHODS

Eight patients with lower lip carcinomas had defects ranging from one third to four fifths of the length of the lower lip after tumor resection. The defects were closed with sliding labial tissue flaps, taking advantage of the elasticity of soft tissue to reduce the loss of normal tissue. Patients were followed for 2 to 12 years.

RESULTS

The functional and cosmetic results were good, and there were no intra- or postoperative complications. Some patients experienced tightness of the lower lip that disappeared within 6 months. Carcinoma did not recur in any patient after a median follow-up period of more than 5 years.

CONCLUSIONS

This modified labial tissue sliding flap technique is simple, safe, functionally and aesthetically satisfactory, sacrifices little healthy tissue, heals rapidly, and requires no further revision. The technique is effective for repairing defects covering one third to four fifths of the lower lip.

Vasopeptidase inhibition attenuates the progression of renal injury in subtotal nephrectomized rats

BACKGROUND

Vasopeptidase inhibitors are a new class of cardiovascular compounds that inhibit both angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). The aim of the present study was to explore the effects of omapatrilat, a vasopeptidase inhibitor, on renal function and pathology in subtotally nephrectomized (STNx) rats.

METHODS

STNx rats were randomized to four groups and treated for 12 weeks: no treatment (N = 14); omapatrilat at a low dose of 10 mg/kg (L, N = 12) and at a high dose of 40 mg/kg (H, N = 10); or an ACE inhibitor, fosinopril, at a dose of 10 mg/kg (N = 12). Sham-operated rats were used as control animals (N = 12).

RESULTS

Elevated blood pressure in STNx rats (174 +/- 9 mm Hg) was reduced by omapatrilat in a dose-dependent manner (L, 121 +/- 3 mm Hg; H, 110 +/- 3 mm Hg) and by fosinopril (149 +/- 5 mm Hg). Proteinuria in STNx rats (246 +/- 73 mg/day) was reduced by treatment with fosinopril (88 +/- 21 mg/day) and was normalized by treatment with omapatrilat (L, 30 +/- 4 mg/day; H, 20 +/- 2 mg/day vs. control 25 +/- 1 mg/day). Decreased glomerular filtration rates, elevated plasma urea and creatinine and glomerulosclerosis, and tubulointerstitial fibrosis were ameliorated by omapatrilat and fosinopril to a similar degree. Compared with fosinopril, omapatrilat treatment was associated with increased plasma renin activity and decreased renal ACE and NEP binding in a dose-dependent manner.

CONCLUSION

These findings suggest that vasopeptidase inhibition may provide a useful strategy for the treatment of progressive renal disease.

Molecular cloning of a cDNA for a putative choline co-transporter from Limulus CNS

It is well documented that the sodium dependent, hemicholinium-3 sensitive, high affinity choline co-transporter is rate limiting in the biosynthesis of acetylcholine and is essential to cholinergic transmission. Until recently this transporter had eluded cloning. Okuda et al. (2000. Nature Neurosci. 3, 120-125) recently reported the successful cloning of the choline co-transporter in Caenorhabditis elegans (CHO-1) and rat (CHT1). We report herein the cloning of the choline co-transporter in the horseshoe crab, Limulus polyphemus. Through the use of a series of degenerate primers selected from consensus sequences of CHO-1 and CHT1, we generated two probes that were used to search a Limulus cDNA library produced from central nervous system (CNS) tissue. The full length nucleotide sequence of the Limulus homolog consists of 3368 bp which includes an open reading frame (ORF) that predicts a protein of 579 amino acids and two non-translation regions (NTR), one at the 3' end and the other at the 5' end. The amino acid sequence has 46% identity with rat CHT1 and 50% identity with both CHO-1 in C. elegans and the recently cloned human co-transporter (hCHT; Apparsundaram et al., 2000. Biochem. Biophys. Res. Commun. 276, 862-867; Okuda and Haga, 2000. FEBS Lett. 484, 92-97). Hydropathy plot analysis predicts the Limulus choline co-transporter (LChCoT) to have thirteen transmembrane domains (TMD), with the N-terminus oriented extracellularly and the C-terminus oriented intracellularly. Northern blot analyses using cDNA probes designed from LChCoT cDNA sequences revealed its distribution specifically in central nervous system structures. On the other hand it was not found in non-nervous tissues. The successful cloning of LChCoT, which was shown to be a member of the sodium-dependent glucose transporter family (SLGT), should prove useful in the determination of its physiological regulation, including its intracellular trafficking.

[Does response of rape to La and critical concentration of La in red earth]

The effects of different concentration of La added in red soil on the growth, yield, content of chlorophyll and peroxidase(POD) activity of rape were studied by pot experiments. The results showed that the growth and yield of rape could be improved by low concentration of La3+, however there was no significant difference between the treatment and the control, and inhibited when the dose were more than 300 mg kg-1 and killed after 600 mg.kg-1 La was added. The decrease of chlorophyll content and chlorophyll a/b was observed when the exogenous concentration of La was more than 15 mg.kg-1. POD activity increased gradually with increasing concentration and prolonging reaction. The feasible application level of La was suggested to be below 15 mg.kg-1.

Neuronal cyclic AMP controls the developmental loss in ability of axons to regenerate

Unlike neonatal axons, mammalian adult axons do not regenerate after injury. Likewise, myelin, a major factor in preventing regeneration in the adult, inhibits regeneration from older but not younger neurons. Identification of the molecular events responsible for this developmental loss of regenerative capacity is believed key to devising strategies to encourage regeneration in adults after injury. Here, we report that the endogenous levels of the cyclic nucleotide, cAMP, are dramatically higher in young neurons in which axonal growth is promoted both by myelin in general and by a specific myelin component, myelin-associated glycoprotein (MAG), than in the same types of neurons that, when older, are inhibited by myelin-MAG. Inhibiting a downstream effector of cAMP [protein kinase A (PKA)] prevents myelin-MAG promotion from young neurons, and elevating cAMP blocks myelin-MAG inhibition of neurite outgrowth in older neurons. Importantly, developmental plasticity of spinal tract axons in neonatal rat pups in vivo is dramatically reduced by inhibition of PKA. Thus, the switch from promotion to inhibition by myelin-MAG, which marks the developmental loss of regenerative capacity, is mediated by a developmentally regulated decrease in endogenous neuronal cAMP levels.

bcl 10 gene mutation in hepatocellular carcinoma

OBJECTIVE

To detect the mutation frequency of the bcl 10 gene in the early and advanced stages of hepatocellular carcinoma (HCC).

METHODS

Genome DNA samples were extracted from 46 cases of fresh HCC tumor tissues and their non-tumor adjacent tissues. Polymerase chain reaction-single strand conformation polymorphism method was used to detect point mutations of the three exons of the bcl 10 gene. For each individual exon, six random samples from those showing abnormal DNA bands were sequenced to verify those mutations. The relationship between serum alpha-fetoprotein (AFP) level and bcl 10 mutation, between the tumor size and bcl 10 mutation was also analyzed.

RESULTS

Among the 46 samples, 26 cases (56.5%) were found to have mutations in exon 1, 5 out of the 6 cases were shown to have 5744 C-->G mutation by sequencing; 25 cases (54.3%) were found to have mutations in exon 2, 4 out of the 6 cases were shown to have 11,311 T deletion mutation by sequencing. Twenty-one cases (45.7%) were found to have mutations in exon 3, all of the 6 cases selected for sequencing were shown to have 14,116 C-->T mutation. Statistical analysis showed that neither serum alpha-fetoprotein level nor the size of hepatocellular carcinoma has a significant relationship with bcl 10 mutation.

CONCLUSION

The bcl 10 gene has a high mutation frequency in liver cancer.

Irbesartan normalises the deficiency in glomerular nephrin expression in a model of diabetes and hypertension

AIMS/HYPOTHESIS

The location of nephrin has been identified as the slit-diaphragm of the glomerular podocyte. Recent evidence suggests that nephrin could play a key role in the function of the glomerular filtration barrier and the development of proteinuria but its status in long-term diabetes is still not understood. We studied the expression of nephrin in a hypertensive model of diabetic nephropathy and investigated the potential influence of angiotensin II blockade on nephrin gene and protein expression.

METHODS

Streptozotocin-diabetic spontaneously hypertensive rats were given either no treatment or the angiotensin II antagonist, irbesartan, at a dose of 15 mg/kg per day by gavage for 32 weeks. Non-diabetic spontaneously hypertensive rats were used as a control group. Real time RT-PCR and immunohistochemistry were used to assess and quantify gene and protein expression of nephrin.

RESULTS

Diabetic spontaneously hypertensive rats developed albuminuria and had a reduction in both gene and protein expression of nephrin when compared with control rats. Irbesartan treatment prevented the development of albuminuria and completely abrogated the down regulation of nephrin in diabetic rats.

CONCLUSION/INTERPRETATION

Long-term diabetes in spontaneously hypertensive rats is associated with a reduction in both gene and protein expression of nephrin within the kidney. These changes in nephrin levels were completely prevented by angiotensin II antagonist treatment, suggesting a potential novel mechanism to explain the antiproteinuric effect of agents which interrupt the renin-angiotensin system.

Role of the Lewis(x) glycan determinant in corneal epithelial cell adhesion and differentiation

In this study we demonstrate that in corneal epithelium there is cell-cell contact-regulated expression of a 145-kDa glycoprotein (GP) bearing the glycan determinant Lewis(x) (Le(x)) (Galbeta(1,4)[Fucalpha(1,3)]GlcNAc). This glycoprotein (Le(x)-GP) was expressed in confluent/contact-inhibited cultures but not in sparse cultures of corneal epithelium. In contrast, a 135-kDa glycoprotein bearing precursor, unfucosylated, lactosamine-containing glycans (Galbeta1-4GlcNAcbeta1-R) was expressed in sparse cultures. Immunofluorescence staining and confocal microscopy of confluent cultures revealed that in corneal epithelium, Le(x) antigen is located in high density at sites of cell-cell adhesion. In in vitro cell-cell adhesion assays, anti-Le(x), but not anti-sialyl-Le(x) monoclonal antibodies, inhibited the formation of corneal epithelial cell-cell adhesion. Also, when added to confluent cultures, antibodies to Le(x) disrupted the monolayer and caused tightly packed polygonal cells to round up. Analysis of the expression of Fut genes that encode alpha-1,3-fucosyltransferases, the enzymes that generate the Le(x) determinant, revealed that confluent/contact-inhibited cultures of rabbit corneal epithelium contain markedly elevated levels of Fut4 and Fut3/5/6 gene transcripts compared with sparse cultures. These data suggest that the Fut4 and Fut3/5/6 genes are targets of cell-cell contact-regulated signals and that Fut gene products direct cell-cell contact-associated expression of Le(x) on the Le(x)-GP in corneal epithelium. Immunohistochemical analysis revealed that the expression of Le(x) antigen in the epithelium of adult and developing corneas is related to the stage of differentiation of the cells. Although early differentiated cells robustly expressed Le(x), relatively undifferentiated cells did not, and the expression level was relatively low in terminally differentiated cells. Overall, these data provide evidence that a Le(x)-bearing glycoprotein plays a role through the Le(x) determinant in corneal epithelial cell-cell adhesion, and these data suggest that Le(x)-mediated cell-cell interactions contribute to mechanisms that mediate corneal epithelial cell differentiation.

Additive hypotensive and anti-albuminuric effects of angiotensin-converting enzyme inhibition and angiotensin receptor antagonism in diabetic spontaneously hypertensive rats

Angiotensin II plays a pivotal role in the development of diabetic nephropathy, but it remains controversial as to the best approach to effectively block the actions of this hormone in the kidney. The aim of the present study was to explore the effects of long-term treatment (8 months) with a combination of an angiotensin type 1 (AT1) receptor antagonist, irbesartan (15 mg/kg per day), and an angiotensin-converting enzyme (ACE) inhibitor, captopril (100 mg/kg per day), in diabetic spontaneously hypertensive rats. Captopril treatment reduced blood pressure (163+/-3 mmHg versus diabetic 201+/-3 mmHg), but not albumin excretion rate (43.8x//1.3 mg/day versus diabetic 46.8x//1.4 mg/day). Irbesartan treatment was associated with a similar reduction in blood pressure (173+/-3 mmHg) to captopril, and albumin excretion rate was reduced (14x//1.5 mg/day). The combination of irbesartan and captopril induced further reductions in blood pressure (140+/-3 mmHg) and albumin excretion rates (4.0x//1.5 mg/day). Gene expression of transforming growth factor beta-1 was reduced by all treatments to a similar level as assessed by in situ hybridization. These results demonstrate the additive hypotensive and anti-albuminuric effects of an ACE inhibitor and an AT1 receptor, suggesting that combination therapy is an approach not only more effective at reducing blood pressure, but also at retarding the development of diabetic nephropathy.

[Prevention and management of severe hemorrhage during gynecological operations]

OBJECTIVE

To investigate the prevention and management of severe bleeding during gynecological operations.

METHODS

A retrospective study of 85,505 gynecological operations from 21 hospitals in China during the period of 1990-1999 was analyzed.

RESULTS

There were 683 cases with bleeding more than 1,000 ml during surgery, an incidence of 0.80% (range 0.07%-6.98%). Operation for removal of malignant ovarian tumor was the commonest cause of severe bleeding (42.31%); followed by cervical carcinoma (28.71%); endometrial carcinoma (16.11%). Only 6 transvaginal surgeries (0.88%) had severe bleeding. The most common site of bleeding was massive oozing from the raw wound surface, then the paracervical area (15.7%), around sacral ligament (12.14%).

CONCLUSIONS

Advanced malignant tumors, tumors located at retroperitoneal or with extensive adhesion were the main causes of profuse bleeding during operation. Good surgical skill and well understanding of the pelvic anatomy are the basic key points for surgeons, and a supportive anesthesia is also important in reducing hemorrhage during operations. Once bleeding occurs, to stop the bleeding accurately and promptly by pressing, clamping, and suturing, and internal iliac artery ligation may be needed occasionally. Special attention should be paid to the hemostasis of the venous plexus of pelvic floor.

Vascular expression of angiotensin type 2 receptor in the adult rat: influence of angiotensin II infusion

OBJECTIVE

The aim of this study was to investigate the relative role of the angiotensin type 1 (AT1) and type 2 (AT2) receptors in mediating angiotensin II-induced regulation of AT2 receptor in mesenteric artery.

DESIGN

Sprague-Dawley rats were infused with either angiotensin II or vehicle for 14 days at a dose of 58.3 ng/min. Ang II-infused rats were allocated to receive either an AT1 antagonist, valsartan at a dose of 30 mg/kg per day or the AT2 receptor antagonist PD123319 at a dose of 830 ng/min.

METHODS

Gene and protein expression of the AT2 receptor in the mesenteric vasculature was assessed by quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry and by in vitro autoradiography with a specific radioligand, 1251-CGP 42112B.

RESULTS

The AT2 receptor mRNA and protein were detected in the mesenteric artery from adult rats. Both nuclear emulsion and immunohistochemical staining showed expression of the AT2 receptor in the adventitial and medial layers. Compared to control rats, angiotensin II infusion was associated with a significant increase in the AT2 receptor expression. Valsartan treatment significantly reduced AT2 receptor gene expression, with no significant effect of PD123319 on this parameter.

CONCLUSIONS

This study confirms that the presence of the AT2 receptor in mesenteric arteries in adult rats, shows an up-regulation of the AT2 receptor following angiotensin II infusion and suggests a role for the AT1 receptor in this regulation. In view of the recently demonstrated effects of the AT2 receptor, these findings may be relevant to the role of the AT2 receptor in the pathophysiology of vascular remodeling.

[Symbiotic effect of cultivating fish in rice field in north China]

Experiment on rice-fish symbiosis in north China showed that the rice production in rice-fish field was a bit higher than control, and the output-input ratio of energy, utilization efficiency of solar energy and soil organic matter content increased 0.08, 0.1 and 0.24%, respectively. The banded sclerotic blight incidence decreased 3.8% and the net economic income increased 900 RMB yuan per hectare. All the resul;ts showed that rice-fish symbiotic system had a good symbiotic effect.

[A study of prognostic factors of stage IV epithelial ovarian cancer]

OBJECTIVE

To determine the effects of treatments for stage IV epidermal ovarian cancer and detect the prognostic factors.

METHODS

31 cases primarily treated in our hospital from 1990 to 1998 were analyzed retrospectively.

RESULTS

Univariate analysis showed that the number of courses of chemotherapy, the size of residual disease, the histologic cell type, and the metastatic site were the significant prognostic factors(P < 0.05). Cox proportional hazard model confirmed that two factors (the size of residual lesion < or = 2 cm and the cycles of chemotherapy > or = 8 decreased the death odds ratio by 0.28 and 0.72 respectively. Three factors (lack of operation, presence of supraclavicular lymph node involvement and liver involvement) increased the death odds ratio by 14.25 times, 11.44 times and 1.85 times respectively (P < 0.05).

CONCLUSION

Surgical debulking, aggressive and appropriate chemotherapy are important measures to improve survival rate for patients with stage IV epithelial ovarian cancer.

Transforming growth factor-beta receptor-associated protein 1 is a Smad4 chaperone

Members of the transforming growth factor-beta (TGF-beta) superfamily signal through unique cell membrane receptor serine-threonine kinases to activate downstream targets. TRAP1 is a previously described 96-kDa cytoplasmic protein shown to bind to TGF-beta receptors and suggested to play a role in TGF-beta signaling. We now fully characterize the binding properties of TRAP1, and show that it associates strongly with inactive heteromeric TGF-beta and activin receptor complexes and is released upon activation of signaling. Moreover, we demonstrate that TRAP1 plays a role in the Smad-mediated signal transduction pathway, interacting with the common mediator, Smad4, in a ligand-dependent fashion. While TRAP1 has only a small stimulatory effect on TGF-beta signaling in functional assays, deletion constructs of TRAP1 inhibit TGF-beta signaling and diminish the interaction of Smad4 with Smad2. These are the first data to identify a specific molecular chaperone for Smad4, suggesting a model in which TRAP1 brings Smad4 into the vicinity of the receptor complex and facilitates its transfer to the receptor-activated Smad proteins.

Theoretical characterization of photoisomerization channels of dimethylpyridines on the singlet and triplet potential energy surfaces

Photoexcitations and photoisomerizations due to low-lying n pi* and pi pi* excited states of dimethylpyridines are investigated by density functional theory, CASSCF, CASPT2 and MRCI methodologies. Mechanistic details for the formation of Dewar dimethylpyridines and the interconversions of dimethylpyridines are rationalized through the characterization of minima and transition states on the singlet and triplet potential energy surfaces of relevant intermediates. Our present theoretical schemes suggest that Mobius dimethylpyridine intermediate 14 and azabenzvalene intermediate 10 can serve as possible precursors to Dewar dimethylpyridines and singlet phototransposition products, respectively. The calculations suggest that an S1(pi pi*)/S0 conical intersection in dimethylpyridines 2 is involved in the formation of 14. An azabenzvalene 10 might be formed through S2(pi pi*)/S1(n pi*) interaction followed by an S1/S0 decay in dimethylpyridine 6. Calculated barriers of isomerizations from 14 to Dewar dimethylpyridine 7 and from 10 to 4 are 8.4 and 28.5 kcal mol(-1) at the B3LYP/6-311 G** level, respectively. In the suggested triplet multistage transposition mechanism, an out-of-plane distorted geometry 19 due to vibrational relaxation of the T1(3B1) excited state of 3,5-dimethylpyridine 6 is a precursor of the interconversion of 6 to 2.4-dimethylpyridine 4. The formation of a triplet azaprefulvene 21 with a barrier of 20.7 kcal mol(-1) is a key step during the triplet migration process leading to another out-of-plane distorted structure 27. Subsequent rearomatization of 27 completes the interconversion of 6 with 4. Present calculations provide some insight into the photochemistry of dimethylpyridines at 254 nm.

Genomic organization of BmTXKbeta and BmTXKS2, two scorpion venom peptides from Buthus martensii Karsch

To elucidate genomic organization of BmTXKbeta and BmTXKS2, two scorpion venom peptides from Chinese scorpion Buthus martensii Karsch(BmK) were first isolated and their genomic regions characterized using the PCR method. Analysis of nucleotide sequence shows that there exists different intron location in the venom genes. The region encoding mature peptide of BmTXKbeta is disrupted by an intron with 886 bp, whereas the intron of BmTXKS2 is located within its propeptide coding region, which is different from other scorpion toxin genes with their introns within the signal peptide coding region.

Modeling the active sites in metalloenzymes. 3. Density functional calculations on models for [Fe]-hydrogenase: structures and vibrational frequencies of the observed redox forms and the reaction mechanism at the Diiron Active Center

Optimized structures for the redox species of the diiron active site in [Fe]-hydrogenase as observed by FTIR and for species in the catalytic cycle for the reversible H(2) oxidation have been determined by density-functional calculations on the active site model, [(L)(CO)(CN)Fe(mu-PDT)(mu-CO)Fe(CO)(CN)(L')](q)(L = H(2)O, CO, H(2), H(-); PDT = SCH(2)CH(2)CH(2)S, L' = CH(3)S(-), CH(3)SH; q = 0, 1-, 2-, 3-). Analytical DFT frequencies on model complexes (mu-PDT)Fe(2)(CO)(6) and [(mu-PDT)Fe(2)(CO)(4)(CN)(2)](2)(-) are used to calibrate the calculated CN(-) and CO frequencies against the measured FTIR bands in these model compounds. By comparing the predicted CN(-) and CO frequencies from DFT frequency calculations on the active site model with the observed bands of D. vulgaris [Fe]-hydrogenase under various conditions, the oxidation states and structures for the diiron active site are proposed. The fully oxidized, EPR-silent form is an Fe(II)-Fe(II) species. Coordination of H(2)O to the empty site in the enzyme's diiron active center results in an oxidized inactive form (H(2)O)Fe(II)-Fe(II). The calculations show that reduction of this inactive form releases the H(2)O to provide an open coordination site for H(2). The partially oxidized active state, which has an S = (1)/(2) EPR signal, is an Fe(I)-Fe(II) species. Fe(I)-Fe(I) species with and without bridging CO account for the fully reduced, EPR-silent state. For this fully reduced state, the species without the bridging CO is slightly more stable than the structure with the bridging CO. The correlation coefficient between the predicted CN(-) and CO frequencies for the proposed model species and the measured CN(-) and CO frequencies in the enzyme is 0.964. The proposed species are also consistent with the EPR, ENDOR, and Mössbauer spectroscopies for the enzyme states. Our results preclude the presence of Fe(III)-Fe(II) or Fe(III)-Fe(III) states among those observed by FTIR. A proposed reaction mechanism (catalytic cycle) based on the DFT calculations shows that heterolytic cleavage of H(2) can occur from (eta(2)-H(2))Fe(II)-Fe(II) via a proton transfer to "spectator" ligands. Proton transfer to a CN(-) ligand is thermodynamically favored but kinetically unfavorable over proton transfer to the bridging S of the PDT. Proton migration from a metal hydride to a base (S, CN, or basic protein site) results in a two-electron reduction at the metals and explains in part the active site's dimetal requirement and ligand framework which supports low-oxidation-state metals. The calculations also suggest that species with a protonated Fe-Fe bond could be involved if the protein could accommodate such species.

Exchangeability of N termini in the ligand-gated porins of Escherichia coli

The ferric siderophore transporters of the Gram-negative bacterial outer membrane manifest a unique architecture: Their N termini fold into a globular domain that lodges within, and physically obstructs, a transmembrane porin beta-barrel formed by their C termini. We exchanged and deleted the N termini of two such siderophore receptors, FepA and FhuA, which recognize and transport ferric enterobactin and ferrichrome, respectively. The resultant chimeric proteins and empty beta-barrels avidly bound appropriate ligands, including iron complexes, protein toxins, and viruses. Thus, the ability to recognize and discriminate these molecules fully originates in the transmembrane beta-barrel domain. Both the hybrid and the deletion proteins also transported the ferric siderophore that they bound. The FepA constructs showed less transport activity than wild type receptor protein, but the FhuA constructs functioned with turnover numbers that were equivalent to wild type. The mutant proteins displayed the full range of transport functionalities, despite their aberrant or missing N termini, confirming (Braun, M., Killmann, H., and Braun, V. (1999) Mol. Microbiol. 33, 1037-1049) that the globular domain within the pore is dispensable to the siderophore internalization reaction, and when present, acts without specificity during solute uptake. These and other data suggest a transport process in which siderophore receptors undergo multiple conformational states that ultimately expel the N terminus from the channel concomitant with solute internalization.

Structure-activity relationship of alkyl camptothecin esters

The cytotoxicity of camptothecin (CPT) esters 1-6 was measured. Like parental camptothecin, esters 2 and 3, but not 1, 4, 5, and 6, inhibited proliferation of human leukemia cells in culture and induced programmed cell death as assessed by flow cytometry studies. Exhibition of similar levels of antiproliferative activities of CPT 2 and 3 required different incubation time periods in cell cultures, with CPT and 3 requiring the shortest and longest periods, respectively. Both 2 and 3 were inactive against cells resistant to the semisynthetic CPT derivative 9-nitrocamptothecin and unable to stabilize DNA-topoisomerase I (Topo I) "cleavable complexes" in a cell-free system, suggesting that Topo I activity was required but insufficient for the mechanism of action of 2 and 3. Mouse liver homogenate converted esters to parental CPT, but the conversion rates were different with different esters. Of four tested esters in this experiment, ester 2 had the fastest conversion rate. In vivo studies showed that ester 2 had an exceptional lack of toxicity in nude mice, even at enormous doses, and demonstrated extensive activity against human breast and colon tumors grown as xenografts in immunodeficient nude mice, whereas no antitumor activity was observed for the other esters. In conclusion, ester 2 is a prodrug of the antitumor compound CPT, and it can be administered at very high doses in mice with no appearance of toxicity. This study provides a basis for further evaluation of CPT ester 2 as an investigational anticancer agent.

Dependence of anticancer activity of camptothecins on maintaining their lactone function

Camptothecins contain a lactone ring that exists in the closed form below ph 7. Above 7, the open (CPT+) and the closed (CPT) form coexist in a 50-50 ratio in mouse plasma and in a 90-10 ratio in human plasma due to the high affinity of human serum albumin (HSA) for CPT+. CPT+ is much less toxic than CPT and it is excreted much faster. In complete RPMI 1640 culture medium, the equilibrium CPT(+)-CPT is 50-50. If 4% HSA is added, it moves to 90-10 modeling for the human physiological situation.

The quantitative distribution of a putative PKC epsilon mRNA in Limulus central nervous system by modified competitive RT-PCR

Recently, a full length cDNA for the epsilon (epsilon) isoform of protein kinase C (PKC) was cloned and sequenced from a cDNA library for the horseshoe crab, Limulus polyphemus. This multifunctional enzyme has been implicated in the modulation of the choline cotransporter in Limulus and the epsilon isoform has been identified in homogenates from its central nervous system (CNS). RT-PCR has proven to be a very useful method for quantifying even a few molecules of mRNA in tissue samples. A modified competitive RT-PCR was used here to quantify a putative PKC epsilon mRNA in Limulus CNS preparations. First, we replaced normally used oligo dT and random primers generated from mRNA with a PKC epsilon specific (3' end) primer P4. Then we used modified nucleotides to extend sample life in storage and finally, we used only annealing and denaturing temperatures during PCR to reduce background. The modified method was used for the first time to quantify PKC epsilon mRNA from three distinct areas of the CNS in Limulus. Results revealed high levels of PKC epsilon mRNA in the corpora pedunculata, in the abdominal ganglia and in the brain ring. These results indicate that PKC epsilon mRNA is broadly distributed throughout the Limulus CNS. Importantly, this modified competitive RT-PCR technique was successfully applied to the quantitation of specific mRNA from Limulus nervous tissue for which no internal standard is available commercially.

Interferon-inducible protein 10 induction and inhibition of angiogenesis in vivo by the antitumor agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA)

5,6-Dimethylxanthenone-4-acetic acid (DMXAA), a drug synthesized in this laboratory that halts tumor blood flow and induces tumor hemorrhagic necrosis in transplantable murine tumors, is known to induce the synthesis of antiangiogenic cytokines in vitro. We have measured the induction of mRNA for modulators of angiogenesis in vivo and investigated whether DMXAA may also have an additional antiangiogenic action through the production of these cytokines. The genes for IFN-alpha and for interferon-inducible protein 10 (IP-10) were strongly induced in both spleen and Colon 38 tumor tissue after DMXAA treatment, whereas that for IFN-gamma was induced in spleen but not in tumor. Expression of mRNA for IFN-beta and for the p35 or the p40 subunits of interleukin 12 was not observed in either tissue. Splenic IP-10 mRNA induction was not a result of IFN-gamma production induced with DMXAA because spleen tissue from DMXAA-treated mice that lacked functional IFN-gamma receptors expressed similar amounts of IP-10 mRNA as those from wild-type mice. A single i.p. injection of DMXAA (20 mg/kg) was sufficient to reduce fibroblast growth factor-induced endothelial cell invasion of Matrigel implants in athymic nude mice by nearly 100%. The inactive analogue 8-methylxanthenone-4-acetic acid did not up-regulate the genes for IP-10 or IFNs and did not inhibit endothelial cell invasion. Antibodies to IP-10 reversed the inhibition of DMXAA of endothelial cell invasion by 58%; antibodies to tumor necrosis factor-alpha, IFN-gamma, and IFN-alpha reversed inhibition by 7%, 5%, and 0%, respectively. The data support the hypothesis that DMXAA, in addition to antivascular effects mediated by tumor necrosis factor-alpha, may have an antiangiogenic effect mediated largely by the induction of IP-10.

Mitochondrial DNA deletion mutations colocalize with segmental electron transport system abnormalities, muscle fiber atrophy, fiber splitting, and oxidative damage in sarcopenia

The in vivo cellular impact of age-associated mitochondrial DNA mutations is unknown. We hypothesized that mitochondrial DNA deletion mutations contribute to the fiber atrophy and loss that cause sarcopenia, the age-related decline of muscle mass and function. We examined 82,713 rectus femoris muscle fibers from Fischer 344 x Brown Norway F1 hybrid rats of ages 5, 18, and 38 months through 1000 microns by serial cryosectioning and histochemical staining for cytochrome c oxidase and succinate dehydrogenase. Between 5 and 38 months of age, the rectus femoris muscle in the hybrid rat demonstrated a 33% decrease in mass concomitant with a 30% decrease in total fibers at the muscle mid-belly. We observed significant increases in the number of mitochondrial abnormalities with age from 289 +/- 8 ETS abnormal fibers in the entire 5-month-old rectus femoris to 1094 +/- 126 in the 38-month-old as calculated from the volume density of these abnormalities. Segmental mitochondrial abnormalities contained mitochondrial DNA deletion mutations as revealed by laser capture microdissection and whole mitochondrial genome amplification. Muscle fibers harboring mitochondrial deletions often displayed atrophy, splitting and increased steady-state levels of oxidative nucleic damage. These data suggest a causal role for age-associated mitochondrial DNA deletion mutations in sarcopenia.

[Immunorelated pancytopenia]

OBJECTIVE

A report of a group of patients with pancytopenia which might be related to abnormal immunity.

METHODS

The clinical and laboratory features of 29 patients with positive bone marrow mononuclear cell (BMMNC) Coombs tests were analyzed.

RESULTS

Most of these cases were pancytopenia with normal or decreased bone marrow cellularities and increased normoblasts. They were all found to have negative results of conventional hemolysis tests and hematopoietic nutrient determination and had no evidence of malignant clonal hematopoiesis. However, all of them showed positive BMMNC-Coombs test and good response to corticosteroids.

CONCLUSION

Immunorelated pancytopenia might be caused by abnormal immunity (especially autoantibody) mediated destruction or abnormal function of blood cells. It is beneficial to differentiate immunorelated pancytopenia from aplastic anemia or myelodysplastic syndromes.

Study of iron metabolism abnormality in the hepatocyte damage of hepatitis B

OBJECTIVE

To study the effect of iron metabolism on patients with hepatitis B.

METHODS

Hemoglobin (Hb), serum ferritin (SF), transferritin (TRF), serum iron (SI), and total iron binding capacity (TIBC) were detected in 103 patients with hepatitis B and 20 healthy adults.

RESULTS

The severer the hepatocyte damage was, the higher the SF, SI and the lower the Hb, TRF, and TIBC were. Furthermore, it seems more obvious among fulminant hepatitis and liver cirrhosis.

CONCLUSIONS

The overload of iron may enhance the hepatocyte damage induced by HBV. Therefore, to detect serum markers of iron metabolism is helpful to evaluate curative effect and prognosis of hepatitis B.

[Study on the cytochrome P450 activity in alkane converting process of Candida tropicalis]

A method of reduced CO-difference spectrum was established to study the cytochrome P450 activity of the whole cell of Candida tropicalis during the alkane converting process. Using this method, the cytochrome P450 activities of the whole cells that were cultured in the different concentrations of alkane were studied. The results showed that the 5% alkane could induce the cytochrome P450 activity obviously but not inhibit the growth of cells, so it was determined preliminarily that the alkane concentration of the seed medium was 5%. The cytochrome P450 activities of dicarboxylic acid (DCA) fermentation processing were further studied. During the exponential phase of growth, the cytochrome P450 activity increased smoothly. However, during the phase of production of dicarboxylic acid, the cytochrome P450 activities increased rapidly after a sort decrease. The results still showed that the rate of production of dicarboxylic acid increased with the cytochrome P450 activity.

[Basement membrane in squamous cell carcinomas of the larynx: an immunohistochemical study]

OBJECTIVE

The study was to assess the distribution of basement membrane(BM) in laryngeal squamous cell carcinomas(LSCC). Correlation of BM and clinical parameters (TNM stage, histological grading, invasion mode, lymph node metastasis) was also examined.

METHODS

The expression of BM around tumor cell was determined in 40 cases of LSCC by using monoclonal antibody against human type IV collagen. An intact continuous BM was found in 17 cases (42.5%), while partial or widespread loss of the BM was detected in the other 23 cases (57.5%).

RESULTS

In cases with poor histological differentiation, the defect of BM was more severe than that in cases with high or middle histological differentiation (P < 0.05). Moreover, diffuse invasion carcinomas revealed lower type IV collagen expression comparing with cases with better tumor-host border (P < 0.05). There was a higher risk of regional lymph node metastasis among cases with poor BM expression (P < 0.01), but there was no association of clinical stage with BM defect (P > 0.05).

CONCLUSION

These observations indicated that testing the distribution of BM seems to be useful to evaluate the histological grading of malignancy of laryngeal carcinoma and be helpful to prognosticate the frequency of regional lymph node metastasis.

[A quantum chemical study of pi-back-donation bond and Raman intensity of 1 sigma + electronic state of Pt-CO molecule]

The Raman spectroscopic properties of Pt-CO molecule have been investigated based on the electronic state 1 sigma + determined by the HF and B3LYP methods. The result shows that the calculated stretching vibrational frequencies of the Pt-C and C-O bonds depend on the method and the basis sets used. It indicates that it is important to adopt an appropriate method to describe pi-donation and pi-back-donation bond. The result of the differential Raman scattering cross section for the stretching vibrations of the Pt-C and C-O bond shows that the latter is significantly larger value compared to the former.

Angiotensin type 2 receptor is expressed in the adult rat kidney and promotes cellular proliferation and apoptosis

BACKGROUND

Angiotensin II (Ang II) is associated with cell proliferation and apoptosis. The role of the angiotensin type 2 receptor (AT2R) in these processes remains controversial. Conventional radioligand binding of 125I-Sar1, Ile8 Ang II in adult kidney has failed to demonstrate the binding for the AT2R.

METHODS

The presence of the AT2R was explored in adult rat kidney by in vitro and in vivo autoradiography using the selective AT2R radioligand 125I-CGP 42112B. The roles of the angiotensin type 1 receptor (AT1R) and the AT2R in mediating cellular proliferation and apoptosis were assessed using selective AT1R or AT2R antagonists in Ang II-infused Sprague-Dawley (SD) rats.

RESULTS

125I-CGP 42112B binding was demonstrated by in vitro and in vivo autoradiography techniques in the glomeruli and proximal tubules of SD rats. This binding could be displaced by Ang II and the AT2R antagonist PD123319 but not by the AT1R antagonist valsartan. Subcutaneous infusion of Ang II for 14 days in eight-week-old SD rats induced proliferation of proximal tubular epithelial cells, as assessed by a twofold increase in proliferating cell nuclear antigen (PCNA)-positive cells and apoptosis, as assessed by a threefold increase in terminal dUTP nick end labeling (TUNEL)-positive cells. The administration of the AT2R antagonist PD123319 or the AT1R antagonist valsartan was associated with attenuation of the increases in both PCNA- and TUNEL-positive cells following Ang II infusion. Ang II infusion was associated with increased osteopontin gene and protein expression, which could be reduced by treatment with either valsartan or PD123319.

CONCLUSION

These findings indicate that there is significant expression of the AT2R in the adult kidney, and that the AT2R has a role in mediating Ang II-induced proliferation and apoptosis in proximal tubular epithelial cells and expression of osteopontin.

[Effects of electromagnetic radiation from cellular telephone handsets on symptoms of neurasthenia]

In order to study the effects of electromagnetic radiation from cellular telephone handsets on symptoms of neurasthenia, 115 and 101 persons with or without handsets were selected. The subjects were investigated by questionnaire on their general health, lifestyle, habit, mental stress, the frequency of using the handsets, living and working environment, the cases of suffered from diseases and symptoms of neurasthenia. The data were analyzed by Chi-square test and Logistic regression statistics. The results showed that the time of using handset was positively associated with depression (P < 0.05), nausea (P < 0.01) and loss of appetite(P < 0.05). The results showed that long time use of cellular telephone handset could induce the symptoms of neurasthenia.

Blockade of the renin-angiotensin and endothelin systems on progressive renal injury

The renin-angiotensin system (RAS) and endothelin system may both play a role in the pathogenesis of progressive renal injury. The aims of the present study were 3-fold: first, to explore the possible benefits of dual blockade of the RAS with an ACE inhibitor and an angiotensin type 1(AT1) receptor antagonist; second, to examine the relative efficacy of endothelin A receptor antagonism (ETA-RA) compared with combined endothelin A/B receptor antagonism (ETA/B-RA); and third, to assess whether interruption of both RAS and endothelin system had any advantages over single-system blockade. Subtotally nephrectomized rats were studied as a model of progressive renal injury and randomly assigned to one of the following treatments for 12 weeks: perindopril (ACE inhibitor), irbesartan (AT1 receptor antagonist), BMS193884 (ETA-RA), bosentan (ETA/B-RA), and a combination of irbesartan with either perindopril or BMS193884. Treatment with irbesartan or perindopril was associated with an improved glomerular filtration rate and reductions in blood pressure, urinary protein excretion, glomerulosclerosis, and tubular injury in association with reduced gene expression of transforming growth factor-beta(1) and matrix protein type IV collagen. The combination of irbesartan with perindopril was associated with further reductions in blood pressure and urinary protein excretion. No beneficial effects of either BMS193884 or bosentan were noted. Furthermore, the addition of BMS193884 to irbesartan did not confer any additional benefits. These findings suggest that the RAS but not the endothelin system is a major mediator of progressive renal injury after renal mass reduction and that the combination of an AT1 receptor antagonist with an ACE inhibitor may have advantages over the single agent of RAS blocker treatment.

[Long-term follow-up result of partial laryngectomy]

OBJECTIVE

To study the long-term follow-up result of partial laryngectomy and reservation of laryngeal function.

METHODS

Three hundred and seventy-nine patients who underwent partial laryngectomy from 1986 to 1995 were summarized (male 290 cases, female 89 cases). Among them, 184 cases were supraglottic carcinomas (T1 8 cases, T2 115, T3 48, T4 13, according to UICC in 1992), 192 cases were glottic carcinomas (T1 115, T2 63, T3 13, T4 1), 3 cases were transglottic carcinomas (T2 1, T3 2). In common 8 kinds of operations were performed: 26 cases underwent cordectomy, 138 vertical laryngectomy, 7 frontolateral laryngectomy, 12 horizontal glottic laryngectomy (middle part of the larynx), 58 supraglottic laryngectomy, 95 horizontovertical (3/4) laryngectomy, 24 subtotal laryngectomy with cricoglossoepiglottic anastomosis, 19 near-total laryngectomy with cricoglossal anastomosis (with reservation of unilateral arytenoid cartilage). 193 cases underwent concurrent neck dissection(121 unilateral, 72 bilateral).

RESULTS

All cases restored their phonation and overcame aspiration with removing nasal feeding from 7 to 23 days after operations. 362 cases were decannulated from 9 days to 3 months after operations. Another 8 cases were decannulated after a secondary plastic operation. Decannulation rate was 97.6%. The three, five and ten year survival rates were 86.8% (329/379), 81.3% (266/327) and 69.4% (120/173) respectively.

CONCLUSION

Partial laryngectomy is a kind of radical operation with reservation of laryngeal function. Mastering indications strictly, correct operation choices, excellent surgical skills and perfect repairing technique are bases of improving life qualities and curative effect.

Binding of ferric enterobactin by the Escherichia coli periplasmic protein FepB

The periplasmic protein FepB of Escherichia coli is a component of the ferric enterobactin transport system. We overexpressed and purified the binding protein 23-fold from periplasmic extracts by ammonium sulfate precipitation and chromatographic methods, with a yield of 20%, to a final specific activity of 15,500 pmol of ferric enterobactin bound/mg. Periplasmic fluid from cells overexpressing the binding protein adsorbed catecholate ferric siderophores with high affinity: in a gel filtration chromatography assay the K(d) of the ferric enterobactin-FepB binding reaction was approximately 135 nM. Intrinsic fluorescence measurements of binding by the purified protein, which were more accurate, showed higher affinity for both ferric enterobactin (K(d) = 30 nM) and ferric enantioenterobactin (K(d) = 15 nM), the left-handed stereoisomer of the natural E. coli siderophore. Purified FepB also adsorbed the apo-siderophore, enterobactin, with comparable affinity (K(d) = 60 nM) but did not bind ferric agrobactin. Polyclonal rabbit antisera and mouse monoclonal antibodies raised against nearly homogeneous preparations of FepB specifically recognized it in solid-phase immunoassays. These sera enabled the measurement of the FepB concentration in vivo when expressed from the chromosome (4,000 copies/cell) or from multicopy plasmids (>100,000 copies/cell). Overexpression of the binding protein did not enhance the overall affinity or rate of ferric enterobactin transport, supporting the conclusion that the rate-limiting step of ferric siderophore uptake through the cell envelope is passage through the outer membrane.

Deficiency of T2K leads to apoptotic liver degeneration and impaired NF-kappaB-dependent gene transcription

Induction of NF-kappaB-dependent transcription requires phosphorylation and subsequent degradation of I-kappaB, an inhibitor of NF-kappaB, followed by nuclear translocation and DNA binding of NF-kappaB. Tumor necrosis factor receptor-associated factor 2 (TRAF2) plays a role in NF-kappaB activation in response to cytokines such as tumor necrosis factor alpha (TNFalpha). In this study, we purified and characterized a novel kinase (T2K, also known as TBK1 or NAK), which associates with TRAF2 and exhibits kinase activity towards I-kappaBalpha in vitro. The physiological function of T2K was investigated using T2K-deficient mice. Heterozygotes appear normal, but t2k(-/-) animals die at approximately E14.5 of massive liver degeneration and apoptosis. Never theless, hematopoietic progenitors from T2K-deficient fetal liver support normal lymphocyte development. Furthermore, t2k(-/-) embryonic fibroblasts and thymocytes do not display increased sensitivity to TNFalpha-induced apoptosis. In response to either TNFalpha or IL-1 induction, t2k(-/-) embryonic fibroblasts exhibit normal degradation of I-kappaB and kappaB-binding activity. However, NF-kappaB-directed transcription is dramatically reduced. These results demonstrate that, like I-kappaB kinase beta and the RelA subunit of NF-kappaB, T2K is critical in protecting embryonic liver from apoptosis. However, T2K has a unique role in the activation of NF-kappaB-directed transcription, apparently independent of I-kappaB degradation and NF-kappaB DNA binding.

Aromatic components of two ferric enterobactin binding sites in Escherichia coli FepA

Ferric enterobactin is a catecholate siderophore that binds with high affinity (Kd approximately 10-10 M) to the Escherichia coli outer membrane protein FepA. We studied the involvement of aromatic amino acids in its uptake by determining the binding affinities, kinetics and transport properties of site-directed mutants. We replaced seven aromatic residues (Y260, Y272, Y285, Y289, W297, Y309 and F329) in the central part of FepA primary structure with alanine, individually and in double combinations, and determined the ability of the mutant proteins to interact with ferric enterobactin and the protein toxins colicins B and D. All the constructs showed normal expression and localization. Among single mutants, Y260A and F329A were most detrimental, reducing the affinity between FepA and ferric enterobactin 100- and 10-fold respectively. Double substitutions involving Y260, Y272 and F329 impaired (100- to 2500-fold) adsorption of the iron chelate more strongly. For Y260A and Y272A, the drop in adsorption affinity caused commensurate decreases in transport efficiency, suggesting that the target residues primarily act in ligand binding. F329A, like R316A, showed greater impairment of transport than binding, intimating mechanistic involvement during ligand internalization. Furthermore, immunochemical studies localized F329 in the FepA ligand binding site. The mutagenesis results suggested the existence of dual ligand binding sites in the FepA vestibule, and measurements of the rate of ferric enterobactin adsorption to fluoresceinated FepA mutant proteins confirmed this conclusion. The initial, outermost site contains aromatic residues and probably functions through hydrophobic interactions, whereas the secondary site exists deeper in the vestibule, contains both charged and aromatic residues and probably acts through hydrophobic and electrostatic bonds.