Regulation and differential expression of neutral endopeptidase 24.11 in human endothelial cells

Neutral endopeptidase 24.11, a membrane-bound metallopeptidase, cleaves, and degrades vasoactive peptides such as atrial natriuretic peptide, endothelin, angiotensin I, substance P, and bradykinin. Therefore, the presence of this metallopeptidase may contribute to the regulation of vascular tone and local inflammatory responses in the vascular endothelium and elsewhere. We determined neutral endopeptidase in cultured human endothelial cells from different vascular beds and studied its regulation by protein kinase C. Neutral endopeptidase was detected in all cultured endothelial cell types. Lowest concentrations were measured in human endothelial cells from umbilical veins (360 +/- 14 pg/mg protein), followed by pulmonary and coronary arteries; higher concentrations were found in endothelial cells from the cardiac microcirculation (1099 +/- 73 pg/mg protein). Neutral endopeptidase content increased during cell growth but was not affected by endothelial cell growth factor or modifications of the growth medium. Stimulation of protein kinase C with 1-oleoyl-2-acetyl-rac-glycerol (0.1 to 1 mumol/L) and phorbol 12-myristate 13-acetate (0.01 to 0.1 mumol/L) induced a time- and concentration-dependent increase of endothelial cells that was inhibited by cycloheximide (5 mumol/L), an inhibitor of protein synthesis. Incubation with phospholipase C (1 mumol/L) and thrombin (10 IU/mL) induced upregulation of neutral endopeptidase, resulting in 158 +/- 26% and 150 +/- 22% increases, respectively, compared with controls. The thrombin effect was inhibited by calphostin C (1 mumol/L), an inhibitor of protein kinase C. Endothelial neutral endopeptidase is constitutively expressed in endothelial cells from different origins and is inducible by thrombin via activation of the protein kinase C pathway.

T-cell cytokine responses in human infection with Mycobacterium tuberculosis

Compared with healthy tuberculin reactors, Mycobacterium tuberculosis-stimulated peripheral blood mononuclear cells from tuberculosis patients had diminished production and mRNA expression of the Th1 cytokines gamma interferon and interleukin 2 (IL-2), with no change in production and mRNA expression for the Th2 cytokines IL-4, IL-10, and IL-13. These results were confirmed by evaluation of T cells and CD4+ cells. At the level of systemic T cells, development of tuberculosis is associated with diminished Th1 but not enhanced Th2 responses.

Protein engineering and NMR studies of calmodulin

The calcium regulatory protein calmodulin (CaM) plays a role as an on-off switch in the activation of many enzymes and proteins. CaM has a dumbbell shaped structure with two folded domains, which are connected by a flexible linker in solution. The calmodulin-binding domains of the target proteins are contained in 20 residue long amino acid sequences, that share no obvious amino acid sequence homology. In this contribution, we discuss the features of CaM, which allow it to be rather promiscuous, and bind effectively to all these distinct domains. In particular, we describe the role of the methionine-rich hydrophobic surfaces of the protein in providing a malleable and sticky surface for binding many hydrophobic peptides. The enzyme activation properties of various Met --> Leu mutants of CaM are discussed. In addition, the role of the flexible linker region that connects the two domains is also analyzed. Finally, we describe various NMR and spectroscopic experiments that aid in determining the CaM-bound structures of synthetic peptides containing various CaM-binding domains. All structures analyzed to date are alpha-helical when bound to CaM, and they interact with CaM only through amino acid sidechains. This form of protein-protein interaction is rather unique, and may contribute to CaM's capacity to bind effectively to such a wide range of distinct partners.

[Construction and expression of the gene CD4V1V2-PE40, coding for a molecular targeted protein against AIDS]

We here replaced the cell-binding domain in Pseudomonas exotoxin A (PE) with HIV-binding portion of CD4V1V2 molecule and constructed a chimeric gene CD4V1V2-PE40, which can be expressed in E. coli. The hybrid protein displays targeting toxicity toward cells infected by HIV and thus represents a promising novel therapeutic agent for the treatment of AIDS.

Effect of operation variables and monomers on the properties of polyamide microcapsules

Oil containing microcapsules were prepared by using phthaloyl dichloride as an oil-soluble monomer and diethylene triamine (DETA) as a water-soluble monomer. The diameter of the microcapsules decreased and their distribution became narrower and sharper as the emulsifying time was increased within the initial period of 45 s, beyond which no appreciable changes in the diameter and its distribution were observed. Once DETA was introduced into the aqueous solution to initiate the interfacial polycondensation reaction, reducing the stirring speed diminished the formation of the membrane fragments, but resulted in an increase in the microcapsule diameter. This indicates that the strength of the initial membrane is not strong enough to prevent the microcapsules from coalescing. Raising the volume fraction of the dispersed phase led to a larger diameter and a wider distribution of the microcapsules. When ortho-, meta- or para-phthaloyl dichloride was used as the oil-soluble monomer, both the diameter and the zeta-potential of the microcapsules decreased in the order: ortho-->meta-->para-, indicating that the steric effect of the monomers plays an important role in the microencapsulation process.

Endotoxin-induced liver injury and changes in the levels of plasma tumor necrosis factor-alpha and interleukin-6 in rabbits

ELISA was employed to detect changes in plasma TNF-alpha and IL-6 level in rabbits having endotoxin-induced generalized Shwartzman reaction. Liver injury was assessed by the increase of serum ALT and hepatic histopathologic changes. The results showed that plasma TNF-alpha and IL-6 levels increased remarkably 12h after intravenous injection of endotoxin twice at a 24h interval, and these changes corresponded with the degree of liver injury. Coinjection of dexamethasone and endotoxin partly prevented the elevation of TNF-alpha and IL-6 levels and reduced liver injury. These results indicated that TNF-alpha and IL-6 were involved in endotoxin-induced liver injury.

[Clinical application of luteinizing hormone releasing hormone agonist and its impact on bone metabolism]

OBJECTIVES

To evaluate the efficacy of luteinizing hormone releasing hormone agonist (LHRH-A) in the treatment of endometriosis (Em), uterine leiomyoma and adenomyosis, and its impact on bone metabolism.

METHODS

Twenty patients, Em 13 (stage II4, III7, IV2), leiomyoma 4 and adenomyosis 3, were selected to receive LHRH-A 200 micrograms intramuscular daily for 3 months. Clinical and ultrasound features serum follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), osteocalcin (BGP) concentrations were compared before and at the end of treatment. Furthermore, 24-hour urinary calcium (Ca), phosphate (P) excretions and bone mineral density (BMD) of radius and lumbar spine measured by single photon absorptiometry (SPA) and dual energy X-ray absorptiometry (DEXA) were also analysed before and at the end of treatment. Patients were followed-up 3-19 months after discontinuation of the drug.

RESULTS

At the end of treatment dysmenorrhea disappeared in all 15 cases. Pelvic tenderness and induration improved in 18, endometrioma shrinked in 13 cases. Mean uterine volume of 7 patients with leiomyoma or adenomyosis was reduced by 35% from the basal volume. Serum LH, E2 levels were suppressed significantly (P < 0.05), mean E2 concentration declined from 459.5 +/- 292.0 to 160.3 +/- 110.7 pmol/L (P < 0.001). No significant change was found in serum BGP, urinary Ca, P, and BMD of radius and lumbar spine at the end of therapy, The only side effect was mild not flushes and sweating during treatment. After stopping the drug, 17 patients resumed menses within 2 months. Dysmenorrhea and pelvic mass recurred in 6 months with less severity. One became pregnant in 3 months.

CONCLUSIONS

LHRH-A administration is effective in the treatment of Em, leiomyoma and adenomyosis. No significant adverse effect was shown on bone metabolism at the end of 3-month therapy.

Differential expression of elafin in human normal mammary epithelial cells and carcinomas is regulated at the transcriptional level

Elafin is an elastase inhibitor with a unique structure, not related to the serpin family, which includes the neutrophil elastase inhibitor. The gene was identified in this laboratory by subtractive hybridization between RNAs from human mammary tumor-derived cells and cDNAs from normal human mammary epithelial cells. Elafin is consistently expressed in normal mammary epithelial cells, but is down-regulated in most breast tumor cell lines. Restriction fragment analysis detected no gross deletions or rearrangement of the gene in any of the tumor cell lines examined. The elafin gene was cloned, and both the cDNA and the promoter region were sequenced. A major positive upstream promoter element was identified by chloramphenicol acetyltransferase assay and deletion analysis, active in normal cell extracts but not in extracts of tumor cells. These results demonstrate that differential expression of elafin in normal mammary epithelial cells and breast tumor cells is regulated at the transcriptional level. Cell synchronization experiments demonstrated that elafin mRNA is down-regulated in S phase in normal cells. These results suggest that elafin may act as an inhibitor of cell cycle progression.

NMR studies of the methionine methyl groups in calmodulin

Calmodulin (CaM) is a ubiquitous Ca(2+)-binding protein that can regulate a wide variety of cellular events. The protein contains 9 Met out of a total of 148 amino acid residues. The binding of Ca2+ to CaM induces conformational changes and exposes two Met-rich hydrophobic surfaces which provide the main protein-protein contact areas when CaM interacts with its target enzymes. Two-dimensional (1H,13C)-heteronuclear multiple quantum coherence (HMQC) NMR spectroscopy was used to study selectively 13C-isotope labelled Met methyl groups in apo-CaM, Ca(2+)-CaM and a complex of CaM with the CaM-binding domain of skeletal muscle Myosin Light Chain Kinase (MLCK). The resonance assignment of the Met methyl groups in these three functionally different states were obtained by site-directed mutagenesis (Met-->Leu). Chemical shift changes indicate that the methyl groups of the Met residues are in different environments in apo-, calcium-, and MLCK-bound-CaM. The T1 relaxation rates of the individual Met methyl carbons in the three forms of CaM indicate that those in Ca(2+)-CaM have the highest mobility. Our results also suggest that the methyl groups of the unbranched Met sidechains in general are more flexible than those of aliphatic amino acid residues such as Leu and Ile.

Crystal structure of an RNA dodecamer containing the Escherichia coli Shine-Dalgarno sequence

The synthetic dodecameric RNA fragment rUAAGGAGGUGAU resembles a region upstream of the initiation site in prokaryotic mRNAs whereas the pyrimidine-rich complementary strand is identical to the last 12 nucleotides of Escherichia coli 16 S rRNA. The complex thus serves as a model for the Shine-Dalgarno interaction which is required for proper initiation of translation. The crystal structure of rUAAGGAGGUGUA.rAUCACCUCCUUA has been determined at 2.6 A resolution and refined against 2957 1 sigma(F) structure amplitudes to an R-value of 0.195. The unit cell of the triclinic crystals contains two double-stranded RNA molecules. The conformation of the two duplexes is similar, with a root-mean-square deviation of 0.683 A between equivalent atoms, and resembles calf thymus A-DNA as determined by X-ray fiber diffraction methods. Both molecules from continuous helices that penetrate the entire crystal, but the dinucleotide step in between dodecameric duplexes has an unusual geometry with a negative twist angle. The long helices cross over each other in a characteristic manner by inserting the backbone of one molecule into the minor groove of another. These contacts are stabilized by several direct intermolecular hydrogen bonds most of which are mediated by 2'-hydroxyl groups of the ribose sugars suggesting a general mode for the interaction between RNA molecules which is different from DNA-DNA interactions.

[The variable number of tandem repeats in the renin gene of rats and possible significance in hypertension]

The variable number of tandem repeats (VNTR) in the first intron of renin gene for the spontaneously hypertensive rat (SHR), its controls Wistar-Kyoto (WKY), renal hypertensive rat, and Sprague-Dawley rat (SD) were compared by polymerase chain reaction (PCR) method. An analysis of VNTR from WKY, Wistar and SD showed that there are two different renin gene alleles and three genetypes 2.0kb/2.0kb, 2.0kb/1.8kb, 1.8kb/1.8kb. The genetype from renal hypertensive rats is same as those seen in the normal controls. However, compared with the WKY, Wistar and SD genes, a "deletion" of approximately 1.0kb was found in the first intron of the SHR renin gene. Our results strongly suggest that the cause and mechanism of elevated blood pressure is complex, and the molecular basis of the genetic-prone hypertension is existed.

[Morphine blocked the exitatory amino acid mediated membrane current in ambigual motoneurons of the rat]

Excitatory postsynaptic potentials (EPSPs) and responses of neurons in the compact formation of the neucleus ambiguus (AMBc) to pressure-ejected or bath-applied test substances were recorded intracellularly from sagittal slices of Sprague-Dawley rat medulla containing subnucleus centralis of solitary complex (NTSc), AMBc and solitarioambigual pathway. In 5 cells, recorded spontaneous EPSPs could be blocked by morphine (3-5 pmol) to AMBc. Electrical stimulation of NTSc evoked EPSPs in AMBc neurons, the amplitude of which were decreased to 71.1 +/- 6.2% (P < 0.001) with the addition to morphine. The morphine effect could be abolished by bath-applied naloxone (50 nmol/L). The amplitude of membrane depolarization induced by pressure-ejected N-methyl-D-aspartate (NMDA, 0.5-1.0 pmol), acetylcholine (3 pmol) and quisqualate (0.1-0.5 pmol) to NTSc could also be decreased by bath-applied morphine (10 mumol/L) respectively to 38.1 +/- 5.7% (P < 0.001), 32.8 +/- 5.5% (P < 0.01) and 29.6 +/- 7.1% (P < 0.05). The above results suggest that morphine is capable of block by NMDA, ACh and non-NMDA receptors, increaseing the M-current and decreasing the permeability of Na+ and Ca2+.

[Cloning and sequencing of the gene PE40, coding for a portion of Pseudomonas exotoxin A]

Gene PE40 coding for a mutant form of Pseudomonas Exotoxin A was devoid of its native cell binding domain, and was amplified from the total DNA of P. aeruginosa PA103 by PCR. After being sequenced, it was cloned into expressional vector pBV220 to get a recombinant plasmid, which will be useful in the research of molecular targeted protein.

[Effects of verapamil on left ventricular diastolic dysfunction]

To assess the effects of verapamil on left ventricular relaxation and filling dynamics in patients with left ventricular diastolic dysfunction (LVDD), Doppler echocardiography (DE) and cardiac catheterization (Cath) were simultaneously performed in 30 cases with LVDD. The left ventricular filling and relaxation indices were measured with DE and Cath respectively, before and after intravenous injection of verapamil. The result showed that after verapamil injection all left ventricular filling measured with DE were significantly improved in all cases, while left ventricular relaxation indices showed significant improvement only in patients with hypertrophic cardiomyopathy and hypertensive heart disease but no changes in patients with old myocardial infarction. There were no significant correlations between left ventricular filling and relaxation indices. It is concluded that the major mechanism of left ventricular filling improvement induced by verapamil is the reduction of left ventricular afterload and verapamil has different therapeutic effects on LVDD with different etiology.

Cosmic Ray and Solar Particle Investigations Over the South Polar Regions of the Sun

Observations of galactic cosmic radiation and anomalous component nuclei with charged particle sensors on the Ulysses spacecraft showed that heliospheric magnetic field structure over the south solar pole does not permit substantially more direct access to the local interstellar cosmic ray spectrum than is possible in the equatorial zone. Fluxes of galactic cosmic rays and the anomalous component increased as a result of latitude gradients by less than 50% from the equator to -80 degrees . Thus, the modulated cosmic ray nucleon, electron, and anomalous component fluxes are nearly spherically symmetric in the inner solar system. The cosmic rays and the anomalous nuclear component underwent a continuous, -26 day recurrent modulation to -80.2 degrees , whereas all recurring magnetic field compressions and recurring streams in the solar wind disappeared above approximately 55 degrees S latitude.

Catalytically critical nucleotide in domain 5 of a group II intron

Domain 5 (D5) is a small hairpin structure within group II introns. A bimolecular assay system depends on binding by D5 to an intron substrate for self-splicing activity. In this study, mutations in D5 identify two among six nearly invariant nucleotides as being critical for 5' splice junction hydrolysis but unimportant for binding. A mutation at another site in D5 blocks binding. Thus, mutations can distinguish two D5 functions: substrate binding and catalysis. The secondary structure of D5 may resemble helix I formed by the U2 and U6 small nuclear RNAs in the eukaryotic spliceosome. Our results support a revision of the previously proposed correspondence between D5 and helix I on the basis of the critical trinucleotide 5'-AGC-3' present in both. We suggest that this trinucleotide plays a similar role in promoting the chemical reactions for both splicing systems.

[Inhibitory effect of heparin on glomerular mesangial cell]

The pure mesangial cells (MsC) were isolated from the culture of rat glomeruli. After identification, they were divided into heparin-treatment group and control group. It was found that heparin profoundly inhibited the growth of MsC with 75.9% inhibitory rate by means of direct counting MsC. MTT method proved that the inhibitory effect of heparin on MsC was dose-dependent. Electronmicroscopic observation revealed dilated endoplasmic reticulum and Golgi vesicles, more secondary lysosomes, prominent myelin figures and decreased microfilaments in the cytoplasm of the MsC exposed to heparin. Immunocytochemical studies showed that the amounts of FN and LM in the cytoplasm of MsC decreased after heparin treatment. Immunocytochemical investigation also confirmed that heparin could inhibit the expression of nuclear oncogene c-fos and c-jun in the MsC stimulated by PMA. The significance and possible mechanism of inhibitory effect of heparin on MsC were discussed.

Effects of tetrandrine on rabbit platelet aggregation and platelet activating factor generation

AIM

To study the effects of tetrandrine (Tet) on platelet aggregation and platelet activating factor (PAF) generation in rabbit platelet-rich plasma (PRP).

METHODS

The aggregation rate of platelets induced by calcimycin (Cal) and PAF and the inhibition rate of Tet on platelet aggregation were measured. The amount of PAF in PRP stimulated with Cal and treated with Tet was also measured.

RESULTS

Cal 1-8 mumol.L(-1) and PAF 9.5-190.5 pmol.L(-1) induced platelet aggregation. At the final concentrations of 4-64 mumol.L(-1), Tet inhibited the aggregation induced by Cal 4 mumol.L(-1) and PAF 142.9 pmol.L-1. The IC50 (95% confidence limits) were 8.6 (6.0-12.2) mumol.L-1 for Cal and 14.0 (6.4-30.4) mumol.L(-1) for PAF. In the PRP aggregation by Cal, there was a marked increase in PAF content. Tet dependented the release of PAF from platelets by Cal in a concentration-dependent manner, with IC50 of 21 (8-54) mumol.L(-1).

CONCLUSION

The inhibition effect of Tet on platelet aggregation might be concerned with the reduction of endogenous PAF generation.

OHC response recruitment and its correlation with loudness recruitment

After proper noise exposure, Hensen's cells, which have been shown to follow closely the response characteristics of the outer hair cells, suffered a loss of sensitivity at low and moderate SPLs. The lower the stimulus level, the greater was the loss. When the low-SPL loss did not exceed about 40 dB, input-output functions showed an increased rate of amplitude growth, so that the post-exposure response caught up with its pre-exposure counterpart between 60 and 90 dB SPL, depending on the severity of the loss. These results, together with preceding clinical observations, led us to the conclusion that loudness recruitment occurs at least in part at the hair cell level and is basically a local event as opposed to a pathological spread of excitation. The response recruitment we have discovered appears to result from a decreased effect of the active feedback when the passive cochlear mechanisms are intact. Evidence for these relationships is presented and an explanation is offered for previous experimental successes and failures in observing a steepening of rate-intensity functions in auditory nerve fibers after noise exposures or administration of ototoxic drugs.

[The development of skin external expander and clinical applications]

The skin external expander that was designed and developed by the authors is a new device to produce extra skin tissue for the repair of defects by continuous traction over the skin. Clinical application in 38 cases since June 1993 have shown that the method has following advantages: easy in manipulation, unnecessary to bury the expander under the skin, safe and less complications with reliable effects. Accurate measurement of the expanded skin can be obtained with the method. Six months' follow-up of 18 cases demonstrated satisfying results.

Improved targeting of radiolabeled streptavidin in tumors pretargeted with biotinylated monoclonal antibodies through an avidin chase

Radiolabeled streptavidin can be accumulated in tumors pretargeted with biotinylated anti-tumor antibodies. However, circulating biotinylated antibody and endogenous biotin may interfere with the tumor targeting of streptavidin. To reduce biotinylated antibody concentration in the blood, we injected avidin before streptavidin administration. The effects of avidin administration on the biodistribution and tumor targeting of radiolabeled streptavidin were examined.

METHODS

Biotinylated anti-human colon cancer monoclonal antibody (MAb) MLS128 was injected intravenously into nude mice bearing human colon cancer xenografts for pretargeting. After intraperitoneal injection of avidin, radioiodinated streptavidin was administered and its biodistribution and tumor accumulation was investigated.

RESULTS

Radioiodinated streptavidin specifically localized in the tumor pretargeted with biotinylated antibody. Avidin preadministration accelerated the tumor uptake and blood clearance of radioiodinated streptavidin. The tumor-to-blood radioactivity ratio at 6 and 24 hr after radiolabeled streptavidin injection were 1.23 +/- 0.29 and 3.04 +/- 0.86, respectively, in mice with avidin chase (mean +/- s.d., n = 7), and 0.82 +/- 0.17 and 2.29 +/- 0.29, respectively, in those without chase (mean +/- s.d., n = 7).

CONCLUSION

Localization of radiolabeled streptavidin in tumors pretargeted with biotinylated MAb could be improved by avidin chase. This approach may be useful for tumor radioimmunoimaging and radioimmunotherapy.

[Application of computer for measuring the skin area during external expansion]

The skin external expander has been used to produce extra skin and soft tissue by continuous traction of the skin. The computer image measurement technique was designed to accurately measure the extra skin. The paper describes the technique and its clinical applications.

CM101, a polysaccharide antitumor agent, does not inhibit wound healing in murine models

CM101 (previously called GBS toxin), a new anticancer polysaccharide that induces inflammatory reactions in neovasculature of tumors, does not cause similar reactions in neovasculature of healing wounds. It appears that treatment with CM101 will not interfere with normal wound healing in cancer patients.

ADL dependence and medical conditions in Chinese older persons: a population-based survey in Shanghai, China

OBJECTIVE

To describe the prevalence of activities of daily living (ADL) dependence and medical conditions and the relationship between illnesses and ADL performance in the older population of Shanghai, China.

DESIGN

Probability sample survey of community residents.

SETTING

The Jing An district of Shanghai, China. The interviews were carried out at the homes of the older persons.

PARTICIPANTS

There were 3763 noninstitutionalized elders screened, 3745 of whom completed the interview.

MEASUREMENTS

The dependent variables were the five basic ADL items: eating, dressing, transferring, toileting, and bathing. The independent variables were dementia and 19 self-reported medical conditions, along with age, gender and education level.

MAIN RESULTS

Of those in Shanghai aged 65 and older, 8.28% (6.52% of males, 9.17% of females) were functionally dependent in one or more ADLs. The most prevalent self-reported illness was cardiovascular disease, including hypertension (29.12%) and heart disease (26.65%). ADL performance was associated with dementia and a number of medical conditions in univariate analysis. The best predictors of functional dependence in both age groups (65-74 years; 75 years and older), based on the multiple logistic regression analysis and after controlling for age, gender, and education, were stroke, dementia, Parkinson's disease, diabetes, and emphysema.

CONCLUSIONS

The authors have successfully applied five ADL items selected and culturally adapted from Older Americans Resources and Services to the study of older Chinese. A consistent and reliable estimate of functional dependence among older persons is obtained. The prevalence of dementia and many self-reported illness, as well as the ADL status by medical condition, are reported. The findings reveal certain patterns of relationship between illness conditions and ADL performance.

[Assessment by three-dimensional CT of pleural indentation or invasion by peripheral lung cancer]

We evaluated the effectiveness of three-dimensional (3D) CT for pleural indentation or invasion by peripheral lung cancer adjacent to pleura. Pleural indentation was shown in three of nine cases on conventional CT, and six cases were demonstrated three-dimensionally. 3D-CT was superior to conventional CT in demonstrating pleural indentation. Pleural invasion could not be assessed on 3D-CT because the pleura adjacent to the tumor was not visualized.

Studies on the structure and function of glycosylated and nonglycosylated neu differentiation factors. Similarities and differences of the alpha and beta isoforms

Comparative analyses of both glycosylated and nonglycosylated neu differentiation factor (NDF) isoforms revealed significant similarities and differences of their overall structures and functions. Biophysical analyses confirmed that all NDF isoforms are monomeric, but have an extended ellipsoidal shape in solution. All full-length NDFs are similar in secondary and tertiary structures and they contain no alpha-helix but are abundant in beta-strand structures. A small NDF fragment containing only the epidermal growth factor domain is also rich in beta-strand structures, but exhibits tertiary structure different from the long NDF forms. Monoclonal antibodies that selectively recognize epidermal growth factor domains of human NDF-alpha and -beta can specifically bind the respective NDF-alpha and -beta isoforms independent of NDF origins. Western blot analysis and quantitative binding assays further identify that an NDF preparation produced naturally from Rat1-EJ cells contains both alpha and beta isoforms in a 3 to 2 ratio. In receptor-binding competition experiments, human and rat NDF-beta isoforms have higher affinity than NDF-alpha isoforms. NDF-beta isoforms can dramatically enhance the stimulation of DNA synthesis for transfected NIH3T3 cells that overexpress HER-3 and HER-4 receptors, while NDF-alpha isoforms can only stimulate proliferation of HER-4-transfected cells with lower activity. Taken together, NDF-alpha and -beta isoforms share similar gross protein conformations but are biologically distinct.

MyoD protein accumulates in satellite cells and is neurally regulated in regenerating myotubes and skeletal muscle fibers

MyoD belongs to a family of helix-loop-helix proteins that control myogenic differentiation. Transfection of various non-myogenic cell lines with MyoD transforms them into myogenic cells. In normal embryonic development MyoD is upregulated at the time when the hypaxial musculature begins to form, but its role in the function of adult muscle remains to be elucidated. In this study we examined the cellular locations of MyoD protein in normal and abnormal muscles to see whether the presence of MyoD protein is correlated with a particular cellular behaviour and to assess the usefulness of MyoD as a marker for satellite cells. Adult rats were anaesthetised and their tibialis anterior or soleus muscles either denervated, tenotomised, freeze lesioned, lesioned and denervated, or lesioned and tenotomised. At various intervals after the operations the rats were killed and their muscles removed, snap frozen, and sectioned with a cryostat along with muscles from unoperated neonatal and adult rats. The sections were processed for immunohistochemistry using a rabbit affinity-purified antibody to recombinant MyoD. MyoD proved to be an excellent marker for active satellite cells; satellite cells in neonatal and regenerating muscles contained high levels of MyoD protein. MyoD positive cells were not observed in the muscles of old adults, in which the satellite cells are fully quiescent. MyoD immunoreactivity was rapidly lost from satellite cell nuclei after they fused into myotubes and was not detected in either sub-synaptic or non-synaptic nuclei of mature fibers. Denervation, and to a lesser extent tenotomy, of lesioned muscles induced expression of MyoD in myotubal nuclei. Denervation of normal muscles also upregulated MyoD in muscle fiber nuclei, an effect which was maximal after 3 days. We conclude that MyoD protein is neurally regulated in both myotubes and muscle fibers.

[The effect of diethyl-dithiocarbamate on the distribution of pingyangmycin in vivo]

Diethyl-dithiocarbamate (DDC) is a compound with wide spectrum of pharmacologic activities. It has been shown to enhance the tumor cytotoxic effect of Pingyangmycin (PYM). In this paper, the effect of DDC on the distribution of 99mTc-labeled PYM in mice bearing subcutaneous transplant of Ehrlich carcinoma is reported. The results indicate that DDC did not affect the absolute concentration of PYM in the tumor but it accelerated its excretion in the urine and decreased the concentration of PYM in the non-tumorous tissues. Therefore, DDC could help alleviate the damaging effect of PYM on normal tissues without affecting its tumor cytotoxic activity.

Breastfeeding practices in Chengdu, Sichuan, China

Barriers to increased breastfeeding rates in Chengdu, Sichuan were investigated in 1992 and 1993. Responses of focus groups showed that ignorance about breastfeeding and belief that the mother's milk was inadequate, and lack of support from their families, places of employment, and the health system acted as barriers to the women's breastfeeding their infants up to the age of four to six months. Subsequently, 363 mothers of 4- to 12-month-old Chengdu infants were surveyed. Although most mothers in both studies said breastmilk was the best food for their infant up to age of four to six months, only about half of the mothers breastfed for longer than one month. Both studies showed that infants who roomed with their mothers after birth were more likely to have been put to their mother's breast earlier, fed colostrum, breastfed somewhat longer, and exclusively breastfed for a somewhat longer period, although their mothers' infant feeding knowledge did not differ. The researchers conclude that Chengdu health workers should teach parents and parents-to-be more about breastfeeding, and that rooming-in be expanded in Chengdu hospitals.

Isolation and characterization of the arginase-encoding gene (arg) from Coccidioides immitis

The arginase (ARG)-encoding gene (arg) of Coccidioides immitis, a human fungal pathogen, was cloned and sequenced. Both the genomic and cDNA sequences are provided. The transcription start point and poly(A) sites were confirmed. The arg gene, which was located on chromosome II of C. immitis by Southern hybridization, is a single-copy gene with two introns and a 966-bp ORF which translates a 322-aa protein of 35.1 kDa. The deduced ARG protein showed 44% identity and 68% similarity to the Saccharomyces cerevisiae ARG.

Radioimmunoimaging of colon cancer xenografts with anti-Tn monoclonal antibody

Tn antigen is a glycosylated tumor associated antigen and a murine monoclonal antibody, MLS128, has been identified to react with it. The potential of MLS128 for the radioimmunoimaging of colorectal cancer was studied. MLS128 was labeled with radioiodine by the chloramine-T method or indium-111 (111In) by using isothiocyanatobenzyl EDTA, and was injected into nude mice bearing human colon cancer xenografts. Radiolabeled MLS128 showed a high and specific localization in xenografted tumor. At 48 h after injection, the %ID/g of 125I-labeled MLS128 in the tumor was 34.69, whereas that of isotype matched control antibody, FLOPC21, was 5.58 and the tumor-to-nontumor radioactivity ratios of 125I-labeled MLS128 reached to 4.56, 17.84 and 23.62 for the blood, liver and bone, respectively. 111In-labeled MLS128 showed similar results. High accumulation of MLS128 in xenografted tumors suggested that the monoclonal antibody MLS128 is promising for radioimmunoimaging of colorectal cancer.

Metabolic Engineering of a Pentose Metabolism Pathway in Ethanologenic Zymomonas mobilis

The ethanol-producing bacterium Zymomonas mobilis was metabolically engineered to broaden its range of fermentable substrates to include the pentose sugar xylose. Two operons encoding xylose assimilation and pentose phosphate pathway enzymes were constructed and transformed into Z. mobilis in order to generate a strain that grew on xylose and efficiently fermented it to ethanol. Thus, anaerobic fermentation of a pentose sugar to ethanol was achieved through a combination of the pentose phosphate and Entner-Doudoroff pathways. Furthermore, this strain efficiently fermented both glucose and xylose, which is essential for economical conversion of lignocellulosic biomass to ethanol.

[Observation on dynamics of circulating antigen from patients with cysticercosis before and after treatment]

The dynamics of circulating antigen (CAg) level in sera form patients with cysticercosis before and after albendazole treatment were detected by using monoclonal antibody-based double antibody sandwich ELISA (McAb-ELISA). The results indicate that after the patients with cysticercosis had been treated for one, two and three treatment courses, the levels of CAg in sera decreased with the increase in the number of treatment courses, their average OD value dropped from 0.499 before treatment to 0.291, 0.073 and 0.051 after treatment, respectively, and the corresponding negative conversion rates of CAg detection were 20.0%, 57.9% and 87.5%, respectively. Sera from eight patients who had received three courses of albendazole treatment were detected for CAg and CAb before and after treatment. The results indicate that the CAb level dropped rather slowly after three courses of treatment as compared to CAg level. It is concluded that detecting circulating antigen might be used as a promising method for evaluating the drug efficacy.

Activation of adenylate cyclase and phosphodiesterase inhibition enhance neutral endopeptidase activity in human endothelial cells

Endothelial neutral endopeptidase (EC 3.4.24.11, NEP) contributes to the inactivation of vasoactive and inflammatory peptides such as f-Met-Leu-Phe, substance P, atrial natriuretic peptide, and bradykinin. The aim of the present study was to investigate the cellular regulation of NEP expression in human endothelial cells, focusing on the role of cyclic nucleotides and cellular phosphodiesterases (PDE). Activation of adenylate cyclase by forskolin or prostaglandin E1 (PGE1) induced an increase of NEP activity and NEP protein after 24 h of incubation. This effect was mimicked by two activators of protein kinase A, dibutyryl-cAMP and 8-bromo-cAMP. The nonspecific PDE inhibitor, 3-isobutyl-1-methylxanthine (200 microM), increased NEP activity up to 192%. The activator of guanylate cyclase, sodium nitroprusside (SNP), did not affect NEP activity but completely inhibited the 3-isobutyl-1-methylxanthine-mediated increase of NEP activity. The PDE-III inhibitors motapizone (100 microM) and enoximone (100 microM) enhanced NEP activity up to 188% and 213%, the PDE-IV inhibitor rolipram (3 microM) up to 162%, and the combined PDE-III/IV inhibitor zardaverine (1 microM) up to 176% of control values. The present data provide evidence for a cAMP-mediated increase of NEP activity in human endothelial cells.

[A study on relationship between balance of serum lipoprotein and the phlegm damp-blood stasis syndrome differentiation of coronary heart diseases]

75 patients were divided into A,B and C group. The LDL-C was 2.97 +/- 0.67, 4.05 +/- 0.38 and 5.25 +/- 0.98 mmol/L respectively (P > 0.01); but comparing group A or B with the normal group (D), it had no significant difference (P > 0.05). An abnormal coronary arteriography (CAG) was found in the group A in 62.1% and the group B in 57.6% (P > 0.05), while the group C in 84.6% (P < 0.01). There was unusual serum lipoprotein electrophoretogram (SLPG) in group A 75.9%, group B 84.8% and group C 100%, but it had no change in group D (P < 0.001). Five types of Syndrome Differentiation about the Phlegm damp and blood stasis (PDBS) could be found in the group A,B and C. The incidence (51.5%-55.2%) and abnormality of the SLPG (66.7%-92.5%) and CAG (68.8%-100%) of PDBS type were the highest among them. 82.7% CHD patient's clinical comprehensive diagnosis was in accordance with the SLPG and that of the CAG were 64.0%. As to the abnormal SLPG, the sensitivity and rate of coincidence of CAG was 91.7% and 69.3% (P < 0.05-0.01) respectively. The Syndrome Differentiation of PDBS was valuable in differentiating CHD. The SLPG is a good criterion for the study of CHD in TCM.

[The treatment of deep burn of children's hands with early tangential excision and full-thickness skin grafting]

Eighteen cases (21 hands) with full-thickness burn have been treated with tangential excision and full-thickness skin grafting at early stage since 1990. All the hands recovered with good appearance and function. The method and its indications were summarized.

Physicians contracting with managed care

It has been observed that enrollees in managed care systems such as HMOs and PPOs have lower expenditures and utilization rates than those in conventional insurance plans. Few studies have investigated this issue by examining providers. This paper studies whether physicians with low costs are more likely to sign contracts with HMOs and PPOs in order to help explain the observation of lower expenditures and utilization rates by HMO and PPO enrollees. A logistic regression is applied to the data from the 1984-1985 Physician Practice Costs and Income Survey. The results do not show strong evidence that a physician's likelihood of contracting with HMOs and PPOs is related to the physician's practice costs and utilization pattern. Instead, major factors that significantly affect a physician's decision of contracting with managed care systems are the physician's socio-demographics, the physician's practice region, and the market conditions.

Hospitals contracting with managed care

It has been observed that enrollees in managed care systems such as health maintenance organizations (HMOs) and preferred provider organizations (PPOs) have lower utilization rates and lower expenditures than those in conventional fee-for-service health insurance programs. To date, no study has investigated this issue by examining providers. This paper studies whether lower cost hospitals are more likely to sign contracts with HMOs and PPOs and thus explain the observed lower utilization rates and lower expenditures by HMO and PPO enrollees. A logistic regression is applied to the data from the 1988 AHA Annual Survey of Hospitals. The results show that private hospitals, teaching hospitals, hospitals accredited by JCAHO, hospitals with high case mix index, and hospitals located in MSAs are more likely to contract with HMOs and PPOs than their counterparts. If hospitals with these characteristics have higher costs, then the results do not suggest that hospital costs can explain the lower utilizations and lower expenditures by HMO and PPO enrollees.

Genomic structure and chromosomal localization of processed pseudogenes for human RBP-Jk

The functional gene for human recombination signal sequence-binding protein (RBP-Jk) and corresponding processed psudogenes have been isolated from various species, such as Drosophila, Xenopus, mouse, and human. Here we report the isolation of another two genomic pseudogenes of human RBP-Jk, named K2 and K7, from a cosmid library of Hela cells. The nucleotide sequences of both genes exhibited more than 95% homology to the functional human gene for RBP-Jk. Moreover, they did not contain any intron sequences and were interrupted by several stop codons in all frames. In situ hybridization demonstrated that the pseudogenes, K2 and K7, were localized at chromosomes 9p13 and 9q13, respectively. Their physical maps differed from those of the true functional gene and of the pseudogenes reported previously by Amakawa et al. (1993).

Autoradiographic localization of beta-endorphin binding in the pancreas

Autoradiographic localization of 125I-labeled beta-endorphin binding in the rabbit pancreas demonstrated specific binding in the pancreatic islet cells. Binding was inhibited by (1) nonradioactive beta-endorphin, (2) the opioid antagonist naloxone, (3) the mu receptor agonists morphine and [D-Ala2, (Me)Phe4, Gly(ol)5]enkephalin, (4) the delta receptor agonist [D-penicillamine2, D-penicillamine5]-enkephalin, (5) the mu and delta agonist met-enkephalin and (6) the delta and kappa agonist dynorphin. Specific binding was not clearly demonstrable in the acinar portion of the rabbit pancreas. The binding characteristics of 125I-beta-endorphin in the pancreatic islets were comparable with those of mu and delta opioid receptors in the rabbit brain. In the pancreas, beta-endorphin binding appeared to be concentrated in discrete areas in the islets. Combined immunohistochemistry and autoradiography demonstrated that beta-endorphin binding was primarily concentrated in the glucagon-containing alpha and somatostatin-containing delta cells, but was also found in the insulin-containing beta cells to a lesser extent. Given the intraislet location of the opioid binding sites, and our previous finding of immunoreactive beta-endorphin in the pancreatic beta cells and the inhibitory effect of beta-endorphin on insulin secretion, it appears that beta-endorphin may serve a paracrine or autocrine function in the regulation of pancreatic hormone secretion.

T cell cytokine responses in persons with tuberculosis and human immunodeficiency virus infection

Tuberculosis causes more extensive and life-threatening disease in patients with HIV infection than in immunocompetent persons. To investigate the hypothesis that these severe manifestations of tuberculosis may be due to alterations in cytokine production, we evaluated cytokine patterns in HIV-infected tuberculosis patients. Upon stimulation with Mycobacterium tuberculosis in vitro, PBMC from HIV-infected tuberculosis patients had reduced proliferative and type 1 responses, compared with HIV-seronegative tuberculosis patients. The reduction in proliferative responses was independent of the CD4 cell count, but the reduced type 1 response was a direct result of CD4 cell depletion. There was no enhancement of type 2 cytokine production in HIV-infected patients, although production of IL-10 was prominent in all tuberculosis patients. In HIV-infected tuberculosis patients, M. tuberculosis-induced proliferative responses were significantly enhanced by neutralizing antibodies to IL-10 but not by antibodies to IL-4 or by recombinant IL-12. The M. tuberculosis-induced type 1 response was augmented both by antibodies to IL-10 and by recombinant IL-12. Tuberculosis in the context of HIV infection is characterized by diminished type 1 responses, probably induced by immunosuppressive cytokines produced by macrophages/monocytes, rather than by type 2 cells.