[Experimental study on therapeutical effect of Chinese medicine on polymyositis in guinea pigs]

OBJECTIVE

To study the therapeutical effects of Radix Bupleuri and Ramulus Cinnamomi on virus polymyositis in guinea pigs.

METHODS

Forty polymyositis guinea pigs induced by Coxsackievirus B1 were divided at random into A(n = 15), B(n = 15), C(n = 10) groups. A, B groups were treated with Radix Bupleuri and Ramulus Cinnamomi respectively. C group received no treatment. Sign, muscle enzyme spectrum and pathological changes were compared.

RESULTS

A and B groups became better. C group showed an aggravating trend (P < 0.05).

CONCLUSION

Radix Bupleuri and Ramulus Cinnamomi had therapeutic effect on polymyositis in guinea pigs.

A novel mechanism for vasoconstrictor action of 8-isoprostaglandin F2 alpha on retinal vessels

Using a video-imaging technique, we characterized the effects of 8-isoprostaglandin F2 alpha (8-iso-PGF2 alpha) on retinal vasculature from piglets. 8-Iso-PGF2 alpha potently contracted (EC50 = 5.9 +/- 0.5 nM) retinal vessels. These effects were completely antagonized by the cyclooxygenase inhibitor indomethacin, the thromboxane synthase blocker CGS-12970, the thromboxane receptor antagonist L-670596, and the putative inhibitor of the non-voltage-dependent receptor-operated Ca2+ pathway SKF-96365; constrictor effects of 8-iso-PGF2 alpha were also partly attenuated by the ETA-receptor blocker BQ-123 and an inhibitor of endothelin-converting enzyme, phosphoramidon, but was negligibly affected by the L-type voltage-gated Ca2+ channel blocker nifedipine. Correspondingly, 8-iso-PGF2 alpha elicited endothelin release from retinal preparations, which was markedly reduced by SKF-96365. 8-Iso-PGF2 alpha also increased thromboxane production in the retina and cultured endothelial cells, but not on retinovascular smooth muscle cells; these effects of 8-iso-PGF2 alpha were blocked by indomethacin, CGS-12970, SKF-96365, and EGTA, but not by nifedipine. 8-Iso-PGF2 alpha also increased Ca2+ transients in retinal endothelial cells, which were inhibited by SKF-96365 and EGTA, but not by nifedipine, whereas in smooth muscle cells U-46619, but not 8-iso-PGF2 alpha, stimulated a rise in Ca2+ transients. Finally, H2O2 + FeCl2 (in vitro) and anoxia followed by reoxygenation (in vivo) stimulated formation of 8-iso-PGF2 alpha in the retina. In conclusion, 8-iso-PGF2 alpha-induced retinal vasoconstriction is mediated by cyclooxygenase-generated formation of thromboxane and, to a lesser extent, by endothelin after Ca2+ entry into cells, possibly through receptor-operated channels. Retinal vasoconstriction to 8-isoprostanes might play a role in the genesis of ischemic retinopathies.

[Level of NCF and TNF-alpha in the BALF of ILD patients and their clinical significance]

OBJECTIVE

To investigate the relationship between the level of the neutrophil chemotactic factor(NCF), tumor necrosis factor-alpha(TNF-alpha) in patients with interstitial lung disease(ILD) and the activity of ILD.

METHOD

The NCF activities in the BALF and in the serum from 11 patients with sarcoidosis, 7 with idiopathic pulmonary fibrosis (IPF) and 8 normal subjects were determined using the membrane filter and radio-immunoassay. The level of TNF-alpha was also detected.

RESULT

In the 7 IPF patients, the level of NCF and TNF-alpha (203 +/- 44 cells/10 HP, 11.7 +/- 2.9 ng/L) in the BALF was higher than that in 8 control patients (83 +/- 45 cells/10 HP, 6.5 +/- 1.4 ng/L, P < 0.01). The level of NCF and TNF-alpha in the BALF from 11 patients with sarcoidosis (186 +/- 50 cells/10 HP, 12 +/- 3 ng/L) was highet than those in 8 control patients (P < 0.01). The level of NCF and TNF-alpha in the BALF from patients with IPF was positive correlated with the percentage of neutrophil (NCF: r = 0.89, P < 0.01; TNF-alpha: r = 0.86, P < 0.05). The level of NCF and TNF-alpha in the BALF of patients with sarcoidosis was positive correlated with the percentage of lymphocyte (NCF: r = 0.78, P < 0.01; TNF-alpha: r = 0.73, P < 0.01.

CONCLUSION

The level of NCF and TNF-alpha in the BALF from patients with IPF and sarcoidosis can act as the marker of the activity of alveolitis of IPF and sarcoidosis.

Effect of glucose on production and release of proinsulin conversion products by cultured human islets

Isolated human islets were examined for the rates of conversion and release of newly formed (pro)insulin-like peptides. The rate of proinsulin (PI) conversion was 2-fold slower in human beta-cells (t(1/2) = 50 min) than in rat beta-cells (t(1/2) = 25 min). During the first hour following labeling of newly synthesized proteins, PI represented the main newly formed hormonal peptide in the medium; its release was stimulated 2-fold over the basal level by 20 mmol/L glucose. During the second hour, newly synthesized hormone was mainly released as insulin, with 10- to 20-fold higher rates at 20 mmol/L glucose. Prolonged preculture of the islets at 20 mmol/L glucose did not delay PI conversion, but markedly increased the release of newly formed PI, des(31,32)-PI, and insulin at both low and high glucose levels. Our data demonstrate that 1) the release of PI provides an extracellular index for the hormone biosynthetic activity of human beta-cells; 2) an acute rise in glucose exerts a stronger amplification of the release of converted hormone than in that of nonconverted hormone; and 3) prolonged exposure to high glucose levels results in an elevated basal release of converted and nonconverted PI; this elevation is not associated with a delay in PI conversion, but is attributed to the hyperactivated state of the human beta-cell population, which was recently found to be responsible for an elevation in basal rates of hormone synthesis. These in vitro observations on human beta-cells provide a possible explanation for the altered circulating (pro)insulin levels measured in nondiabetic and noninsulin-dependent diabetic subjects.

Prevention of estrogen carcinogenesis in the hamster kidney by ethinylestradiol: some unique properties of a synthetic estrogen

Ethinylestradiol (EE) has evident paradoxical effects on cancer risk for human breast and hepatic cancer which parallel in some respects its effects on estrogen-induced neoplasms in the hamster kidney and liver. EE has been shown to be only weakly carcinogenic in the hamster kidney, but the most potent carcinogenic estrogen in the hamster liver following prolonged treatment. Unexpectedly, when EE and potent carcinogenic estrogens, such as diethylstilbestrol (DES), 17beta-estradiol (E2) and Moxestrol (MOX), are administered concomitantly, estrogen-induced carcinogenesis in the kidney is completely prevented. In studying this novel finding, we found that, compared with E2 exposure alone, EE at 0.05 and 1.0 nM significantly (P < 0.001) inhibited the rise in proliferation of cultured primary hamster proximal renal tubular (PRT) cells in the presence of E2 (1.0 nM). Consistent with these findings, combined EE + DES treatment for 5.0 months reduced hamster kidney c-myc, c-fos and c-jun RNA expression to 43, 37 and 52%, respectively, compared with levels observed after DES treatment alone. Interestingly, TAM + DES treatment for the same period also resulted in the same low level of RNA expression of these proto-oncogenes. c-MYC, c-FOS and c-JUN protein products were comparably reduced after either EE + DES or TAM + DES treatment. It appears that c-fos expression and c-FOS protein levels in the hamster kidney were more responsive to TAM inhibition. These data demonstrate that EE possesses unique anti-tumorigenic properties in vivo in the hamster kidney. Additionally, the observed anti-estrogen-like effect of EE on cell proliferation of cultured PRT cells suggests that EE may interfere critically with estrogen receptor (ER)-mediated mitogenic pathway(s) affected by potent carcinogenic estrogens, thus preventing subsequent gene dysregulation and, hence, tumor development. Based on competition studies, the differential binding of EE to hamster kidney ER relative to that of the other estrogens (E2, DES, MOX) appears not to contribute to the prevention of estrogen carcinogenesis at this organ site by EE.

[Study on the determination of trace metals in complex matrices by chelation ion chromatography]

In this paper, a new method for determination of trace metal ions in complex matrices by chelation ion chromatography has been developed. In accordance to different analysis purpose, different interference should be selectively eliminated. On the chelating resins, all anions, alkali and alkaline earth metals could be eluted by ammonium acetate eluent (pH 5.5), tervalent cations could be eluted by pyrophosphoric acid/ammonium acetate eluent (pH 5.5). On sulfonated cation exchanger, heavy metals, transition metals, iron and aluminum could be eluted by hydrochloric acid/ethanol and oxalic acid/nitric acid eluents. Then, the concentrated lanthanides and transition metals (Pb, Cu, Cd, Ni, Zn and Co) were separated on bifunctional ion-exchange ion-exchange column by a proper concentration gradient of eluents, coupled with post-column spectrophotometric detection. Test samples could be injected directly into the column for analysis after the sample digestion. The detection limits of the method (signal-to-noise = 3:1) were at or below microgram/L level. The method has been systematically applied in rock, alloy, soil, plant and animal samples.

Ethanol modulates cocaine-induced behavioral change in inbred mice

We recently conducted a study of the behavioral effects of combined cocaine and ethanol in genetically defined mice. Male and female C57BL/6 (B6) and DBA/2 (D2) were tested in an automated activity monitor on 2 consecutive days. On day 1, all animals received an IP injection of sterile saline and were placed into the activity monitor for 30 min. Behaviors measured were total distance traveled, stereotypy, nosepokes, and wall-seeking. On day 2, all animals were tested again for 15 min following injection of one of the following: saline, 10% v/v ethanol at 2.0 g kg(-1) or 2.0 g kg(-1) ethanol plus 5, 15, or 30 mg kg(-1) cocaine. Cocaine alone at the same doses was injected into separate groups of animals. For the B6 strain, the overall effect of ethanol was to reduce cocaine-induced locomotor stimulation; no consistent effect of ethanol on cocaine-induced locomotion was observed in D2 mice. Cocaine-induced inhibition of nosepokes in both strains and sexes was partially reversed by ethanol. Ethanol also partially reversed cocaine-elevated stereotypy in both strains and both sexes. In B6 mice, cocaine-increased wall seeking tended to be reversed by coadministration of ethanol, whereas no consistent pattern was observed in the D2s. Results from this study suggest that the several measures affected by cocaine (locomotor activity, stereotypy, exploration, thigmotaxis) were, in turn, differentially affected by concurrent treatment with ethanol. Furthermore, our results point to genetic-based differences in ethanol's effects on cocaine-related behaviors. We address the implications for combined ethanol and cocaine use in humans.

Chinese dietary composition and intakes of elements and radionuclides by ingestion

As update and complement of Chinese Total Diet Study in 1990, a renewing study was conducted during 1992-1993 according to regulated procedure. Contents of 32 elements, including 19 newly determined, in 12 categories of food from 12 provinces were analyzed by NAA or AAS technique and the daily intakes of Chinese adult man were estimated and hygienically evaluated. Meanwhile, a typical survey on dietary composition and intake for difference among 4 age groups and between Spring and Autumn was surveyed too. The results provide important basis for decision for further improvement of Chinese diet from hygienic view point and compilation of physiological characteristics of Chinese Reference Man. At the end of this article, the estimated nationwide average intakes for adult man are compared with those for current ICRP Reference Man.

Sex and strain influence the effect of ethanol on central monoamines

OBJECTIVE

We recently investigated the effects of EtOH on the mesolimbic dopamine and serotonin systems in male and female C57BL/6 (B6) and DBA/2J (D2) mice.

METHOD

Male and female rodents from the B6 and D2 mouse strains (n = 11 per strain, sex and dose) were used in this study. Doses of EtOH (vs saline) administered were 1.0, 2.0 or 3.0 g/kg.

RESULTS

Treatment with saline or EtOH produced both strain- and sex-dependent differences in patterns of monoamine response. For example, D2s exhibited significantly higher overall dopamine (DA) levels than did B6s in the frontal cortex (FC), nucleus accumbens (NA) and caudate-putamen (CP). In the FC, female D2 evinced elevated 5HIAA at 1.0 g/kg. In the NA, D2 females showed dose related increases in levels of DA up to 3.0 g/kg, whereas in the D2 males and in B6 males and females we observed no response. Also in the NA, B6 males showed increases in dihydroxyphenyacetic acid (DOPAC) at 1.0 and 3.0 g/kg. In the CP, B6 males showed higher DA levels than B6 females at the saline, and all EtOH doses. For serotoninergic activity in the CP as well as the NA, EtOH produced a distinctive triphasic response, with the 1.0 and 3.0 g/kg doses of EtOH producing higher levels than saline and 2.0 g/kg of 5HIAA in B6 males than in B6 females.

CONCLUSIONS

Our findings indicate strain and sex differences in monoamine response to acute doses of ethanol, and further implicate (via changes in DOPAC) presynaptic mechanisms in the effects of ethanol on dopamine.

[Determination of tissue chlorine, bromine and iodine concentrations in normal persons with neutron activation method]

Concentrations of chlorine (Cl), bromine (Br) and iodine (I) in heart, liver, spleen, lungs, muscle and hair of normal and healthy persons living in Beijing area were determined with neutron activation method. Results showed that Cl concentrations in variety of tissues, except for hair, were no significant difference. Cl concentration in muscle was slightly less than that in other tissues. Bromine concentrations in lungs and iodine in liver were the highest. Bromine concentration in human tissues was significantly lower in Beijing area than abroad, and iodine was only slightly less and without statistical significance. Furthermore, Cl, Br and I in four kinds of biological standard reference materials were determined, and their results conformed with the recommendation values.

Proinsulin and its conversion intermediates in human pancreas and isolated islet tissue: kinetics and steady-state analysis

In non-insulin-dependent diabetes, circulating insulin-related immunoreactivity (IRI) is often composed of a higher fraction of the incompletely converted forms proinsulin and des-31,32 proinsulin. The present study describes an immunoadsorption method for measuring the proportions of proinsulin, its two split products, and insulin in human pancreatic tissue and for determining their rates of formation in human isolated islets. The method uses two junction-specific monoclonal proinsulin antibodies in a protein G fractionation; it is validated by > or = 90% specificity and recovery. The peptide contents measured in tissue extracts were comparable to those determined in a previously developed immunoradiometric assay. In the nine tissue extracts from nondiabetic donor organs, 97% of IRI corresponded to insulin, 1% to proinsulin, 2% to the des-31,32 proinsulin conversion product, and 0.1% to des-64,65 proinsulin. Two samples from non-insulin-dependent diabetics under sulfonylurea treatment contained a fourfold lower content of IRI but the peptide distribution was comparable except for a low percentage (0.3) of proinsulin in one case. In pulse-chase experiments on three-preparations of human islets isolated from nondiabetic donors, proinsulin represented the major (> 90%) IRI that was synthesized at the end of the 30-min pulse; a subsequent 90-min chase at either 2.5 or 10 mM glucose resulted in conversion of 75% of proinsulin to des-31,32 (20%) and des-64,65 (2%) intermediates and to insulin (50%); after a 180-min chase, 88% of proinsulin was converted to insulin, but 10% remained present as proinsulin. In a pulse-chase experiment on islets isolated from tissue with a high proportion of des-31,32 intermediate (5% instead of 2%), the conversion process was slower (45% after 90 min and 70% after 180 min) and resulted in a higher fraction of des-31,32 intermediate, suggesting that the elevated tissue content in this intermediate is caused by a reduced PC2 converting activity. These data confirm that des-31,32 proinsulin represents the major conversion intermediate in normal human islets and indicate the existence of slow converters, possibly as a result of decreased enzymatic processing of the prohormone's AC junction.

[Study on the analysis of organogermanium compounds by ion chromatography]

A new high performance ion exchange chromatographic method for separation and determination of three organogermanium compounds beta-carboxyethylgermanium sesquioxide (I), beta-(alpha-methyl) carboxyethylgermanium sesquioxide (II) and di-(beta-carboxyethyl) germanium hydroxide (III) has been developed. A Dionex DX-300 Ion Chromatograph equipped with a Dionex PED-II pulsed electrochemical detector (conductivity mode), a Dionex AMMS-1 anion micromembrane suppressor, and a Dionex ACI advanced computer interface coupled with AI-450 chromatographic software was employed. The separation was achieved by using a Dionex IonPac AS4A-SC column as analytical column, sodium tetraborate solution as eluent, and sulfuric acid solution as regenerant. For reducing run time, a gradient program was chosen. The detection limits (S/N = 3, expressed as germanium) for the three compounds were 0.038mg/L (I), 0.035mg/L (II) and 0.025mg/L (III), respectively. The method has been applied to the analysis of two tonic oral drinks, and the average recoveries for the three compounds ranged from 95%-101%. The results obtained were in agreement with those of hydride generation atomic fluorescence spectrometry (HG-AFS).

Characterization of a tunable optical parametric oscillator laser system for multielement flame laser excited atomic fluorescence spectrometry of cobalt, copper, lead, manganese, and thallium in buffalo river sediment

A pulsed (10 Hz) optical parametric oscillator (OPO) laser system based on beta-barium borate (BBO) crystals and equipped with a frequency-doubling option (FDO) was characterized for use in laser excited atomic fluorescence spectrometry (LEAFS). This all-solid-state laser has a narrow spectral line width, a wide spectral tuning range (220-2200 nm), and a rapid, computer-controlled slew scan of wavelength (0.250 nm s-1 in the visible and infrared, and 0.125 nm s-1 in the ultraviolet). The output power characteristics (15-90 mJ/pulse in the visible, 1-40 mJ in the infrared, and 1-11 mJ in the ultraviolet), laser pulse-to-pulse variability (3-13% relative standard deviation, RSD, of the laser pulses), conversion efficiency of the FDO (2-17%), and spectral bandwidth in the visible spectrum (0.1-0.3 cm-1) were measured. The laser was used as the excitation source for a flame LEAFS instrument for which rapid, sequential, multielement analysis was demonstrated by slew scan of the laser. The instrument allowed about 640 measurements to be made in about 6 h, with triplicate measurements of all solutions and aqueous calibration curves, which yielded accurate analyses of a river sediment (National Institute of Standards and Technology, Buffalo River Sediment, 2704) for five elements with precisions < 5% RSD. Comparable or improved flame LEAFS detection limits over literature values were obtained for cobalt (2 ng mL-1), copper (2 ng mL-1), lead (0.4 ng mL-1), manganese (0.2 ng mL-1), and thallium (0.9 ng mL-1) by flame LEAFS.

Determination of bromine and iodine in normal tissues from Beijing healthy adults

The contents of bromine and iodine in samples of heart, liver, spleen, lung, muscle, and hair from healthy adults living in Beijing, China, were determined using epithermal neutron activation analysis. The results indicate that the contents of bromine in lung and iodine in liver are higher than those in other tissues, except human hair. The bromine contents in Beijing human tissues are significantly lower than those in other countries. The contents of iodine are slightly lower than those in other countries, but the difference is not significant. Three biological standard reference materials were simultaneously determined with the samples, and our results agree well with the certified values.

The study of iodine in Chinese total diets

In this work, China was divided into four area groups according to their geographical positions and dietary habits. All foods were divided into 12 types and the iodine contents in various diets were determined using epithermal neutron activation analysis (NAA). The intakes for China were evaluated. The results indicate that the intakes of iodine in northern areas are slightly higher and in south areas lower than the lowest recommended intake, and the average intake in China is 166 micrograms/person per day, which is within the recommended range. In addition, one province were chosen from each area groups. The dietary intakes of iodine were investigated in different ages and sex using total mixed diet method. Our results indicate that the average iodine intake of four provinces was lower than the recommended value, which suggests that it is necessary to supplement iodine in foods in China.

[A new method and instrument for brainlocal hypothermia]

A new method and instrument for brainlocal hypothermia have been introduced in this paper. The instrument provides hypothermia to cerebral blood circulation by using cold probe hyperthemia to body venors blood by using electric heater. So it reduces the temperature only local in brain. This therapy system provides a safe and successful method for brain protection in wide clinical application, such as brain injure emergency, cerebrovascular disease therapy, heart operation etc.

Scanning laser ophthalmoscope imaging of fluorescein-labelled blood cells

PURPOSE

To demonstrate the feasibility of a technique for the visualization by scanning laser ophthalmoscope (SLO) of fluorescein-labelled autologous leukocytes and platelets in retinal vessels.

METHOD

Individual blood samples from rats and rabbits were centrifuged to isolate platelets and leukocytes, then passively labelled with fluorescein and reinjected into the same animal. An SLO was used to visualize and record cell displacement in the retinal circulation. Labelled platelets were analysed by flow cytometry.

RESULTS

By SLO, platelets appeared as a heterogeneous particle flow, and individual leukocytes appearing as brighter spots could easily be traced. Flow cytometry showed that after labelling platelets were well individualized and their size was slightly increased.

CONCLUSION

Circulating blood cells can be visualized in retinal vessels by a simple method consisting of passive labelling of autologous platelets and leukocytes by fluorescein. No platelet toxicity was detected. This method could be applied to the study of blood cell movement in human retinal vascular diseases.

Determination of 19 elements in human eye lenses

Neutron activation analysis was used to determine the concentrations of 19 elements in normal and senile human cataractous lenses. It was found that the concentrations of Ca, Na, Cl, Eu, Sb, and Fe were significantly higher, and those of K, Rb, Cs, Cr, Mn, Co, Sc, and Ce were significantly lower in senile mature cataractous lenses than those in normal human eye lenses. No changes were found for the concentrations of Se, Zn, Mg, S, and Th in the two groups. Positive correlations between Na, Cl, and Ca and K, Rb, and Cs were found, whereas a significantly negative correlation between Na, Ca, Cl and K, Rb, Cs were found. The roles of these elements in the evolution of cataract are discussed.

The cytoplasmic tail of FcgammaRIIIAalpha is involved in signaling by the low affinity receptor for immunoglobulin G

The low affinity receptor for IgG, FcgammaRIIIA, is a multimeric receptor composed of the ligand binding subunit FcgammaRIIIAalpha (CD16) in association with the signal-transducing subunits zeta or gamma. Previous studies suggested that the cytoplasmic tail of FcgammaRIIIAalpha was not required for FcgammaRIIIAalpha-zeta association or signaling by FcgammaRIIIA. However, in these studies, the truncated FcgammaRIIIAalpha chains still expressed the four most membrane-proximal amino acids of the cytoplasmic tail (amino acids 230-233). By successive truncations from the C terminus of FcgammaRIIIAalpha, we have studied the role played by the membrane-proximal amino acids of the cytoplasmic tail of FcgammaRIIIAalpha in (i) FcgammaRIIIA expression, (ii) FcgammaRIIIAalpha-zeta association, and (iii) signal transduction. We provide evidence that this region is not required for FcgammaRIIIA expression or FcgammaRIIIAalpha-zeta association. However, signaling by FcgammaRIIIA is strictly dependent on the membrane-proximal amino acids in the cytoplasmic tail of FcgammaRIIIAalpha. Thus, total deletion of the cytoplasmic tail of FcgammaRIIIAalpha results in a severely impaired tyrosine phosphorylation of phospholipase C-gamma1, zap, and syk and rise in intracellular free Ca2+ following receptor ligation with specific anti-CD16 monoclonal antibody or Ig-anti-Ig complexes, suggesting that FcgammaRIIIAalpha-zeta association per se is not sufficient to establish the signal function of FcgammaRIIIA. In conclusion, the present findings demonstrate that the most membrane-proximal amino acids of the FcgammaRIIIAalpha cytoplasmic tail play a critical role in ligand-induced signal transduction by the FcgammaRIIIAalpha-zeta complex.

Estrogen-induced proto-oncogene and suppressor gene expression in the hamster kidney: significance for estrogen carcinogenesis

Chronic administration of estrogen to male Syrian hamsters for 7.0 to 9.0 months induces a high frequency of estrogen-dependent renal cancers. We have proposed a sequential multistage scheme involving tubular cell damage, regenerative cell proliferation, aneuploidy, chromosomal imbalance, genetic instability, gene alteration, and amplification as essential steps for estrogen carcinogenesis in this model. A systematic study was undertaken to assess the expression of nuclear proto-oncogenes, c-myc, c-fos, and c-jun, and suppressor genes, p53 and WT-1, by Northern blot analysis to further support this scheme. Hamster kidney RNA, taken at monthly intervals (1.0 to 6.0 months) from diethylstilbestrol (DES)-treated castrated male hamsters and corresponding age-matched untreated controls was used in these studies, as well as primary estrogen-induced renal tumor RNA, for reference. Although no significant changes in the expression of these proto-oncogenes were detected in the first 4 months of estrogen treatment relative to age-matched controls, 2.1-kb c-myc expression was elevated 2.8- and 4.1-fold at 5.0 and 6.0 months, respectively. Moreover, the expression of 2.2-kb c-fos transcript rose 4.6- and 4.8-fold; and 3.2- and 2.7-kb c-jun expression increased 2.8- and 5.1-fold at these same respective estrogen treatment time intervals. Tumor suppressor gene expression, p53 and WT-1, was also evaluated in similar estrogen-exposed hamsters. Although no significant changes were found in hamster kidney p53 expression in the first 5.0 months of DES treatment, it rose 1.8-fold at 6.0 months of estrogen treatment and more than 2.0-fold in the primary renal tumor. In contrast, no detectable changes in WT-1 expression were found during the first 6.0 months of DES treatment. However, a dramatic 7.0-fold increase in WT-1 expression was observed in the primary renal tumor. It is evident that two WT-1 transcripts reside in the hamster kidney; a lower molecular weight transcript was found in the normal adult kidney, and a higher molecular weight 3.2-kb transcript was observed in the renal tumor, similar to that seen in the newborn mouse kidney. In summary, the estrogen-induced inappropriate gene expression, including p53, reported herein, is consistent with the view that the elevations seen in gene expression contribute to proliferative advantages of certain proximal tubular interstitial cells necessary for estrogen-driven tumor formation in the hamster.

Stereoselective interaction of uncharged esters at four muscarinic receptor subtypes

We investigated the binding and pharmacological properties of the esters of 3,3-dimethylbutan-1-ol (the carbon analogue of choline) with either diphenylglycolic acid, (R)-phenylcyclohexylglycolic acid, or (S)-phenylcyclohexylglycolic acid [BS-6181, (R)-BS-7826 and (S)-BS-7826, respectively] at muscarinic M1, M2, M3 (Hm3) and M4 receptors. The three uncharged compounds were muscarinic receptor antagonists, with pA2 or pKi values between 7.9 and 5.6. The achiral ester BS-6181 displayed highest affinity for M1, M3 (Hm3) and M4 receptors (pA2 or pKi = 7.2-7.6) and lower affinity for M2 receptors (pA2 or pKi = 6.7 and 6.8). The four muscarinic receptor subtypes were able to distinguish between the two enantiomers of the cyclohexyl derivative of BS-6181 [(R)- and (S)-BS-7826], with a preference for the (R)-isomer (up to 79-fold). Interestingly, the (S)-enantiomer of BS-7826, being the distomer, was found to be M4 selective (pKi/M4 = 6.9; pA2 or pKi/M1-M3 (Hm3) = 5.6-6.2). These results indicate that uncharged compounds may (stereo)selectively bind to muscarinic receptors via hydrophobic interactions. Thus, an ionic bond between muscarinic ligands and an anionic site of the receptor is not absolutely necessary for recognition of muscarinic receptors.

Molecular characterization of the di-leucine-based internalization motif of the T cell receptor

Several cell surface receptors including the T cell receptor (TCR) are phosphorylated and down-regulated following activation of protein kinases. We have recently shown that both phosphorylation of Ser-126 and the presence of the di-leucine sequence Leu-131 and Leu-132 in CD3 gamma are required for protein kinase C (PKC)-mediated TCR down-regulation. To identify additional residues required for PKC-mediated phosphorylation of CD3 gamma and for TCR down-regulation, an alanine scanning of CD3 gamma was done. Mutations of Arg-124, Ser-126, Lys-128, and Gln-129 inhibited both phosphorylation and TCR down-regulation, whereas mutation of Asp-127 only inhibited down-regulation. Further analyses demonstrated a discrepancy between the ability to be phosphorylated on CD3 gamma and to down-regulate the TCR in several transfectants. Phosphorylation was not as strictly dependent on the nature and position of the phosphoacceptor group and basic residues as were the subsequent steps involved in TCR down-regulation. Our results suggest that PKC-mediated TCR down-regulation may be regarded as a two-step process. 1) Recognition and phosphorylation of CD3 gamma by PKC. In this process Arg-124, Ser-126, Lys-128, and Gln-129 are important. 2) Recognition of phosphorylated CD3 gamma by molecules involved in receptor internalization. In this process Ser(P)-126, Asp-127, Leu-131, and Leu-132 are important.

Dual vasoactive effects of tolazoline on rabbit pulmonary arteries

OBJECTIVES

To determine the vasoactive effects of tolazoline on isolated rabbit pulmonary arteries.

DESIGN

Prospective, in vitro, randomized, controlled trial.

SETTING

Experimental laboratory in a university-affiliated hospital.

PARTICIPANTS

New Zealand White Rabbits.

INTERVENTIONS

The pulmonary artery rings were obtained via thoracotomy. Their vasoactive responses were assessed in the presence and absence of intact endothelium and with or without precontraction by norepinephrine (NE, 3 x 10(-6) M) or potassium chloride (KCl, 3 x 10(-2) M). Using a tissue bath preparation, cumulative concentration response curves of tolazoline were obtained at different concentrations (10(-9) to 10(-4) M) after a period of stabilization.

MEASUREMENTS AND MAIN RESULTS

Tolazoline caused vasoconstriction of isolated pulmonary arteries without any pretreatment. The magnitude of the constriction was dose related and reached 300 g/g wet tissue at a concentration of 10(-4) M. On KCl-precontracted pulmonary arteries, tolazoline caused significant dose-related vasoconstriction. On the NE-precontracted vessel rings, it elicited significant dose-dependent vasodilation up to 60% relaxation at 10(-5) M. All the above effects were endothelium independent.

CONCLUSIONS

Tolazoline has dual endothelium-independent vasoactive effects, causing vasoconstriction on isolated rabbit pulmonary arteries, either untreated or precontracted with KCl, and vasodilation on those precontracted with NE. Tolazoline may act as a competitive alpha-adrenoceptor blocking agent.

Influence of monovalent cations on the binding of a charged and an uncharged ('carbo'-)muscarinic antagonist to muscarinic receptors

1. The effect of the buffer concentration on binding of [3H]-N-methylscopolamine to muscarinic receptors M2 was tested in rat heart. Tracer binding was of low affinity in a 20 mM imidazole buffer (pKD 8.3), inhibited by an increase from 10 to 100 mM of the sodium phosphate buffer concentration (pKD 9.92 to 9.22), slightly inhibited by an increase of the Tris/HC1 buffer concentration from 20 to 100 mM (pKD 9.70 to 9.47) and unaffected by an increase of the histidine/HC1 buffer concentration from 20 to 100 mM (pKD 9.90 to 9.82). We chose the last buffer to analyse the effect of ions on antagonists binding to cardiac M2 receptors and to transiently expressed wild-type and (Y533-->F) mutant m3 muscarinic receptors in COS-7 cells. 2. Equilibrium [3H]-N-methylscopolamine binding to cardiac M2 receptors was inhibited, apparently competitively, by monovalent salts (LiCl > or = NaCl > or = KCl). In contrast, binding of the uncharged 3,3-dimethylbutan-1-ol ester of diphenylglycolic acid (BS-6181) was facilitated by addition of monovalent salts (LiCl > or = NaCl > or = KCl) to the binding buffer. This cation binding pattern is consistent with interaction with a large, negative field strength binding site, such as, for instance, a carboxylic acid. 3. In the presence of 100 mM NaCl, [3H]-N-methylscopolamine had a similar affinity for the wild-type m3 receptor (pKD 9.85) and for a (Y533-->F) mutant m3 receptor (pKD 9.68). However, in the absence of added salts, the tracer had a significantly lower affinity for the mutated (pKD 10.19) as compared to the wild-type (pKD 10.70) m3 receptor. BS-6181 had a significantly lower affinity for the (Y533-->F) mutant m3 muscarinic receptor, as compared to the wild-type m3 receptor, both in the absence (pKD 6.19-6.72) in the presence (pKD 6.48-7.40) of 100 mM NaCl. The effects of NaCl on binding of the uncharged ester and of [3H]-N-methylscopolamine to the m3 receptor were decreased by the mutation. 4. Taken together, these results support the hypothesis that monovalent cations from the buffer may interact with the cation binding site of the receptors (an aspartate residue in the third transmembrane helix of muscarinic receptors). Buffer cations may inhibit competitively the binding of (charged) muscarinic ligands having a tertiary amine or ammonium group, while facilitating the receptor recognition by uncharged, isosteric 'carbo-analogues'. Mutation of the (Y533-->F) of the m3 receptor decreased the affinity of the receptor for positive charges, including the sodium ion.

A mouse kidney- and liver-expressed cDNA having homology with a prokaryotic parathion hydrolase (phosphotriesterase)-encoding gene: abnormal expression in injured and polycystic kidneys

To investigate abnormalities in gene expression associated with cyst formation in polycystic kidney disease, differential cDNA library screening was carried out using RNA from normal and cystic kidneys of the C57BL/6J-cpk mouse. Among a number of genes found to be abnormally expressed was one (cDNA clone 56-1) that was significantly underexpressed in cystic kidneys. Hybridization analyses revealed that the 56-1 mRNA is expressed primarily in kidney and liver, and that the kidney expression begins postnatally and continues in the adult. Expression of this mRNA was found to be significantly decreased upon acute renal injury induced by a single intraperitoneal injection of folic acid, and to return to normal levels upon recovery of kidney function. Analysis of the cDNA sequence predicted a protein of 349 amino acids (aa), which was confirmed by in vitro translation of a sense-strand transcript, producing a protein of approx. 39 kDa. The aa sequence shows similarity to Flavobacterium sp. and Pseudomonas diminuta parathion hydrolase (phosphotriesterase or PTE), an enzyme that hydrolyzes toxic organophosphates and other phosphotriesters, and to the predicted product of an Escherichia coli open reading frame of unknown function (phosphotriesterase homology protein or PHP). Use of optimal alignment programs demonstrated a significant overall homology between the bacterial and mouse sequences, with greater than 50% aa sequence similarity. This cDNA represents the first eukaryotic sequence showing similarity to these prokaryotic genes. Based on this apparent homology, it has been named mpr56-1 (for mouse phosphotriesterase-related 56-1).

Role of CD3 gamma in T cell receptor assembly

The T cell receptor (TCR) consists of the Ti alpha beta heterodimer and the associated CD3 gamma delta epsilon and zeta 2 chains. The structural relationships between the subunits of the TCR complex are still not fully known. In this study we examined the role of the extracellular (EC), transmembrane (TM), and cytoplasmic (CY) domain of CD3 gamma in assembly and cell surface expression of the complete TCR in human T cells. A computer model indicated that the EC domain of CD3 gamma folds as an Ig domain. Based on this model and on alignment studies, two potential interaction sites were predicted in the EC domain of CD3 gamma. Site-directed mutagenesis demonstrated that these sites play a crucial role in TCR assembly probably by binding to CD3 epsilon. Mutagenesis of N-linked glycosylation sites showed that glycosylation of CD3 gamma is not required for TCR assembly and expression. In contrast, treatment of T cells with tunicamycin suggested that N-linked glycosylation of CD3 delta is required for TCR assembly. Site-directed mutagenesis of the acidic amino acid in the TM domain of CD3 gamma demonstrated that this residue is involved in TCR assembly probably by binding to Ti beta. Deletion of the entire CY domain of CD3 gamma did not prevent assembly and expression of the TCR. In conclusion, this study demonstrated that specific TCR interaction sites exist in both the EC and TM domain of CD3 gamma. Furthermore, the study indicated that, in contrast to CD3 gamma, glycosylation of CD3 delta is required for TCR assembly and expression.

Effect of exposure to novelty on brain monoamines in C57BL/6 and DBA/2 mice

Male and female mice from two inbred strains, C57BL/6 (B6) and DBA/2 (D2), were exposed to a novel environment (vs. undisturbed control) for 10 min. Immediately after this treatment, the animals were sacrificed by cervical dislocation, and the brains were removed and dissected into ventral midbrain (VMB), caudate-putamen (CP), nucleus accumbens (NA), and medial prefrontal cortex (FC). Analyses of dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and serotonin (5-HT) and its metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA) were made by high-performance liquid chromatography. Utilization of the parent amines was estimated by the ratios, DOPAC/DA, HVA/DA, and 5-HIAA/5-HT. Novelty increased DOPAC levels in NA of both strains of mice and in CP of D2 males; however, it did not induce significant changes in DA, or 5-HT levels or utilization of the latter. The results did, however, reveal large strain differences in DA and its metabolites. The data suggest that genetically based neurophysiological and neurochemical differences exist in dopaminergic and serotonergic systems in mice, and that the DA systems in NA may be more sensitive to novelty than other DA systems.

Duration of inhibition of local microvascular ACE in spontaneously hypertensive rats

OBJECTIVE

To investigate in vivo the duration of inhibition of local angiotensin converting enzyme (ACE) in the microcirculation after a 2-week oral treatment by three different ACE inhibitors.

DESIGN

The local renin-angiotensin system was studied in the microcirculation of cremaster muscle in spontaneously hypertensive rats treated by gavage with equihypotensive doses of trandolapril (0.6 mg/kg per day), enalapril (10 mg/kg per day) and perindopril (2 mg/kg per day) for 2 weeks. Intravital microscopy was used in an original preparation of cremaster isolated from its normal blood supply and externally perfused with physiological solution, allowing exclusion of the circulating converting enzyme. Local ACE activity was estimated by measuring vasoconstriction in response to 0.01 and 0.1 nmol/ml angiotensin I in the arterioles studied and classified as being of second, third and fourth order (mean diameters 58 +/- 6, 30 +/- 4 and 15 +/- 1 mu m for the three orders, respectively).

RESULTS

No difference among the ACE inhibitors was found 3 h after the last dose. Conversely at 7, 24 and 48 h after the last dose, a significant difference was found among the ACE inhibitors, with ACE inhibitors being higher in rats treated with trandolapril than in the other two groups. In addition, a comparison with untreated spontaneously hypertensive rats showed that significant inhibition persisted 48 h after the last dose for trandolapril- and perindopril- but not enalapril-treated rats.

CONCLUSION

Large differences exist between the duration of inhibition of the microvascular ACE in vivo. At that level of the vascular system, trandolapril appeared to provide the greatest duration of inhibition among the three ACE inhibitors tested.

[Correlation between roentgenogram and CT scans with the changes of cells in bronchoalveolar lavage fluid in sarcoidosis]

Considering protean and variability of chest findings of sarcoidosis, the correlation between finding on roentgenogram and CT scans with changes of total, differential cell count and subsets of lymphocytes of BALF in 25 cases with sarcoidosis was studied. The results showed that CT could detect more groups of enlarged lymph nodes in the mediastinum and more minimal lesions in lung parenchyma in those patients who showed stage 0 and I on chest roentgenogram. The parenchymal changes were distributed mainly among the bronchovascular sheath. Good correlation was found between findings on CT scan and total cell count in BALF. Fibrotic changes on CT scan were usually associated with an increase in neutrophils of BALF. It indicated that CT could more precisely assess the lesions in the mediastinum and lung parenchyma and be served as an important supplementary diagnostic measure to roentgenogram for patients with sarcoidosis.

The (S)-(+)-enantiomer of dimethindene: a novel M2-selective muscarinic receptor antagonist

The present study was designed to determine to determine the in vitro affinity profile of (R)-(-)-dimethindene and (S)-(+)-dimethindene at muscarinic receptor subtypes using both functional and binding assays. In addition, the racemate was investigated in functional studies. The functional muscarinic receptors studied were putative M1 receptors in rabbit vas deferens and rat duodenum, M2 receptors in guinea-pig left atria and rabbit vas deferens, as well as M3 receptors in guinea-pig ileum and trachea. Furthermore, the histamine H1 antagonism by (R)-(-)- and (S)-(+)-dimethindene has been examined in guinea-pig ileum. Muscarinic binding selectivity was assessed in homogenates from human neuroblastoma NB-OF 1 cells (M1), rat heart (M2), pancreas (3) and striatum (M4). The results demonstrate that (S)-(+)-dimethindene is a potent M2-selective muscarinic receptor antagonist (pA2 = 7.86/7.74; pKi = 7.78) with lower affinities for the muscarinic M1 (pA2 = 6.83/6.36; pKi = 7.08), the M3 (pA2 = 6.92/6.96; pKi = 6.70) and the M4 receptors (pKi = 7.00), respectively. The (S)-(+)-enantiomer was more potent (up to 41-fold) than the (R)-(-)-enantiomer in all muscarinic assays. In contrast, the stereoselectivity was inverse at histamine H1 receptors, the (R)-(-)-enantiomer being the eutomer (pA2 = 9.42; pA2/(S)-isomer = 7.48). In conclusion, (S)-(+)-dimethindene is a useful tool to investigate muscarinic receptor heterogeneity. In addition, this lipophilic compound might become the starting point for the development of M2-selective muscarinic receptor antagonists useful as diagnostic tools for quantifying muscarinic M2 receptors in the central nervous system with positron emission tomography imaging, and to test the hypothesis that muscarinic M2 receptor antagonists show beneficial effects in the treatment of cognitive disorders.

Comparative vasoactive effects of amrinone on systemic and pulmonary arteries in rabbits

Amrinone has been increasingly used in management of low cardiac output syndrome during anesthesia, particularly when associated with right heart failure and pulmonary hypertension. This in vitro study was performed to determine and compare the direct vasoactive effects of amrinone on isolated rabbit systemic and pulmonary arteries. Responses of aortic and pulmonary artery rings from New Zealand white rabbits were assessed in the presence and absence of intact endothelium and with or without precontraction by norepinephrine (NE, 3 x 10(-6)M) or potassium chloride (KCl, 3 x 10(-2)M). Using a tissue bath preparation, cumulative concentration response curves of amrinone were obtained at different concentrations after a period of stabilization. Amrinone caused a dose-related vasodilation of NE-precontracted aortic and pulmonary arteries. It elicited about 65% and 90% relaxation, respectively, at a concentration of 300 mumol/L. Amrinone also induced a dose-related vasodilation of KCl-precontracted aortic and pulmonary arteries but to a lesser degree. All these effects were endothelium independent. By comparison, amrinone caused more relaxation in both NE- and KCl-precontracted pulmonary artery than aortic rings. In conclusion, amrinone has significant endothelium-independent, direct vasodilatory effects on isolated rabbit systemic and pulmonary arteries, more pronounced in the latter, particularly NE-precontracted vessels. Amrinone may have some calcium channel-blocking effect.

S-100 beta immunoreactivity in neurones of the rat peripheral sensory ganglia

S-100 beta, which is capable of exerting neurotrophic effects on cultured neurones and promoting the survival of motor neurones in vivo, has recently been found in distinct neurones of the rat hindbrain. Here we report that S-100 beta, as well as being present in satellite and Schwann cells, is also present in neurones of sensory ganglia (dorsal root ganglion, trigeminal, petrosal, jugular and nodose ganglia) but absent from neurones of the superior cervical ganglion. In the sensory ganglia, many neurones were immunoreactive, while the staining intensity varied among the neurones. Neuronal S-100 beta appeared in developing rats as early as postnatal day 1. No immunoreactive neurones were observed in the superior cervical ganglion during development. The results are suggestive of selective neurotrophic effects of S-100 beta.

WT1 suppresses synthesis of the epidermal growth factor receptor and induces apoptosis

The Wilms tumor suppressor gene WT1 encodes a developmentally regulated transcription factor that is mutated in a subset of embryonal tumors. To test its functional properties, we developed osteosarcoma cell lines expressing WT1 under an inducible tetracycline-regulated promoter. Induction of WT1 resulted in programmed cell death. This effect, which was differentially mediated by the alternative splicing variants of WT1, was independent of p53. WT1-mediated apoptosis was associated with reduced synthesis of the epidermal growth factor receptor (EGFR), but not of other postulated WT1-target genes, and it was abrogated by constitutive expression of EGFR. WT1 repressed transcription from the EGFR promoter, binding to two TC-rich repeat sequences. In the developing kidney, EGFR expression in renal precursor cells declined with the onset of WT1 expression. Repression of EGFR and induction of apoptosis by mechanism that may contribute to its critical role in normal kidney development and to the immortalization of tumor cells with inactivated WT1 alleles.

[Changes of proteoglycans in lumbar intervertebral disc of bipedal rats with aging]

Using a computer based image analysis system and histological sections stained with Safranin O, we investigated systematically the variation of proteoglycans (PG) contents in the low lumbar discs of bipedal rats. Topographically, the PG concentration increased from the outer annulus to the inner nucleus pulposus region, which possesses the highest PG concentration. The PG content decreased with age, and a significant loss of PG was observed in the lumbar discs of bipedal rats as compared with controls, especially in the nucleus pulposus. These observations support the view that the higher abnormal mechanical stress accelerates disc degeneration.

Vasoactive effects of ketamine on isolated rabbit pulmonary arteries

Ketamine has been used in patients with congenital heart disease and pulmonary hypertension with hypothetical controversy. Its direct effect on pulmonary arteries has not yet been clearly characterized. This in vitro study was performed to determine the direct vasoactive effects of ketamine on isolated rabbit pulmonary arteries. Responses of pulmonary artery rings from New Zealand white rabbits were assessed in the presence and absence of intact endothelium and with or without precontraction by norepinephrine (NE, 3 x 10(-6)M) or potassium chloride (KCl, 3 x 10(-2)M). Using a preparatory tissue bath, cumulative concentration response curves of ketamine were obtained at different concentrations (0.03, 0.1, 0.3, 1, 3 mM) after a period of stabilization. Ketamine caused a dose-related vasodilation on KCl-precontracted pulmonary arteries. It elicited almost 100% relaxation at a concentration of 3 mM. Ketamine also induced a dose-related vasodilation on NE-precontracted pulmonary arteries at a lesser degree. All of the effects were endothelium independent. In conclusion, ketamine has strong endothelium-independent, direct vasodilatory effects on isolated rabbit pulmonary arteries. Ketamine may act through Ca++ channel-blocking effect as well as inhibition of Ca++ release from sarcoplasmic reticulum.

Distinct domains of the CD3-gamma chain are involved in surface expression and function of the T cell antigen receptor

The T cell antigen receptor (TcR) is a multisubunit complex that consists of at least six different polypeptides. We have recently demonstrated that the CD3-delta subunit cannot substitute for the CD3-gamma subunit in TcR cell surface expression, in spite of significant amino acid homology between these two subunits. To identify CD3-gamma-specific domains that are required for assembly of the complete TcR and for surface expression and function of the TcR, chimeric CD3-gamma/CD3-delta molecules were constructed and expressed in T cells devoid of endogenous CD3-gamma. Substitution of the extracellular domain of CD3-gamma with that of CD3-delta did not allow cell surface expression of the TcR. In contrast, substitution of the transmembrane and/or the intracellular domains of CD3-gamma with those of CD3-delta did allow TcR cell surface expression. These results conclusively demonstrate that the extracellular domain of CD3-gamma plays a unique role in TcR assembly. Functional analyses of the transfectants demonstrated that the intracellular domain of CD3-gamma is required for protein kinase C-mediated down-regulation of TcR but is dispensable for the pattern of tyrosine phosphorylation observed following activation through TcR.

Monoclonal antibody induced hearing loss

Monoclonal antibodies KHRI-3 and KHRI-5 identify antigens expressed on inner ear supporting cells and auditory hair cells respectively. To determine if these antibodies affect inner ear function groups of syngeneic Balb/c mice were inoculated with hybridomas KHRI-3, KHRI-5 and other Ig-secreting hybridomas. Hybridomas UM-A9, UM-7F11, the non-secreting SP2/0 myeloma and mice with no hybridoma were used as controls. Animals were tested for auditory brainstem responses (ABR) for frequencies of 4, 8, 16 and 24 kHz, before the inoculation of the hybridomas and at intervals of 6 to 10 days thereafter or daily once tumors became palpable. In normal mice there were no changes in ABR thresholds over the course of the experiment. Other control animals showed little change in ABR even when the growth of the hybridoma or myeloma tumors were far advanced. Of the KHRI-5 hybridoma bearing animals only one of seven animals exhibited threshold shifts greater than 15 dB. In contrast, most mice bearing the KHRI-3 hybridoma exhibited high frequency threshold shifts of 40-50 dB that coincided temporally with the growth of the hybridoma, the presence of circulating KHRI-3 antibody, and greatly increased immunoglobulin titers. Ears from KHRI-3-bearing mice that developed high frequency hearing loss also had a novel type of lesion in the basal turn of the cochlea that was characterized by loss of outer hair cells and absence of typical supporting cell scars. Such changes were not found in control hybridoma-bearing mice. These findings suggest that KHRI-3 antibody has an effect on hearing that is secondary to damage to the organ of Corti and loss of outer hair cells. Our results have important implications for antibody-mediated mechanisms of hearing loss and provide an animal model in which to study this phenomenon.

[An experimental study on the relationship between disc nutrition and disc degeneration]

Micro-angiography, scanning electron microscopy and hydrogen washout technique were used to investigate the disc nutrition condition and the nutritional pathway of endplate in bipedal rats with agting. Compared with the controls, the nutrition condition of bipedal rats underwent deterioration and the number of vascular distribution under the endplate decreased significantly, but no increase in thickness of endplate caused by microfractures of subchondral bone and callus formed during the healing process was observed. The abnormal stress may bring about vertebral body intra-osseous circulation disorder and then consequent decrease of vascular channels which related to the disturbance of disc nutrition. This strongly suggested that nutrition conditions of nucleus pulposus were not deteriorated by impaired diffusion capacity, but by decrease of vasculature that contacts with endplate.

Dual effect of clonidine on isolated rabbit pulmonary arteries

Clonidine, a partially selective agonist for alpha 2-adrenoceptors, has been increasingly used in anesthesia. Its direct effect on pulmonary arteries has not yet been clearly characterized. This in vitro study was performed to determine the vasoactive effects of clonidine on isolated rabbit pulmonary arteries. Responses of pulmonary artery rings from New Zealand white rabbits were assessed in the presence and absence of intact endothelium and with or without precontraction by norepinephrine (NE, 3 x 10(-6) M) or potassium chloride (KCl, 3 x 10(-2) M). Using tissue bath preparation, cumulative concentration response curves of clonidine were obtained at different concentrations (10(-8), 10(-7), 10(-6), 10(-5), 10(-4) M) after a period of stabilization. Clonidine caused vasoconstriction of isolated pulmonary arteries without any pretreatment. The magnitude of the constriction was dose related at lower concentrations and reached maximum of 300 g/g wet tissue when above 10(-6) M. On KCl-precontracted pulmonary arteries, clonidine caused significant dose-related vasoconstriction. On the NE-precontracted vessel rings, it elicited significant dose-dependent vasodilation up to 80% relaxation at 10(-4) M. All the above effects were endothelium independent. In conclusion, clonidine has dual endothelium-independent vasoactive effects, causing vasoconstriction on isolated rabbit pulmonary arteries, either untreated or precontracted with KCl, and vasodilation on those precontracted with NE. Clonidine may act as a competitive alpha-adrenoceptor blocking agent.

Leukocyte adherence in an ischemic muscle perfused by a collateral circulation

Leukocyte adherence was studied in an original experiment that allowed study of the microcirculation in an ischemic muscle perfused by a collateral circulation. In this model, the artery feeding the cremaster muscle was ligated. Then the muscle homolateral to the ligation and its contralateral muscle were both studied by intra-vital-microscopy at 4 h, 1, 3, 7, and 21 days after the ligation. Rats were treated or not with 20 mg/kg/day pentoxifylline (PTX) i.m. In untreated rats, we found that both short-lasting and long-lasting leukocyte adherence was largely increased in the postcapillary venules of the ischemic muscle but not in its contralateral control. This dramatic increase was not limited to the hours immediately after the arterial ligation but was also found up to 3 weeks after the ligation when blood flow was almost restored to normal. This suggested that when muscle blood flow was chronically reduced, some changes promoting leukocyte adherence may occur in the endothelium. In rats treated with PTX, we found very effective inhibition of leukocyte adherence.

Structural requirements for the occupancy of rat brain PACAP receptors and adenylate cyclase activation

N-terminally shortened analogues of PACAP(1-27) and PACAP(1-38), and analogues modified in position 1,2 or 3 were compared for their ability to interact with PACAP receptors and to activate or inhibit adenylate cyclase in rat brain hippocampus membranes. In the PACAP(1-27) series, deletion of the first two amino acids decreased the potency 3000-fold. PACAP fragments (3-27) to (9-27) were inactive on the enzyme. N-terminally shortened PACAP(1-38) analogues showed a similar profile but were 70 to 300-fold more potent than their PACAP(1-27) equivalents. PACAP(6-27) and PACAP(6-38) were competitive inhibitors of the PACAP(1-27) stimulated enzyme. The Kd values of PACAP(6-27) and PACAP(6-38) were of 1000 and 2 nM respectively. Surprisingly, the Kd values of PACAP(6-31) and (6-35), that were also unable to stimulate adenylate cyclase activity, were of 3 and 300 nM respectively. Replacement of His1 by Phe1 in PACAP(1-27) reduced the potency 600-fold. Replacement of Ser2 by Ala2 in PACAP(1-27) and PACAP(1-38) was of little consequence. Substitution of Ser2 by Phe2, DPhe2, Arg2 or DArg2 reduced 60 to 1000-fold the PACAP(1-27) potency but only 7 to 30-fold the PACAP(1-38) potency. Phe2 derivatives were inactive on the enzyme. Replacement of Asp3 by Asn reduced 4000-fold the PACAP(1-27) potency.(ABSTRACT TRUNCATED AT 250 WORDS)

Induction of epidermal growth factor receptor gene transcription by transforming growth factor beta 1: association with loss of protein binding to a negative regulatory element

Transforming growth factor beta (TGF-beta) is a potent modulator of cell growth in many systems. In normal rat kidney fibroblasts, TGF-beta 1 increases epidermal growth factor (EGF) receptor gene transcription and synergizes with EGF to stimulate growth in soft agar, a characteristic of the transformed phenotype. In order to identify the target of TGF-beta 1 action, we have used a series of 5' deletion mutants of the EGF receptor promoter linked to a chloramphenicol acetyltransferase reporter gene (ERCAT). The TGF-beta response element(s) was localized to a cis-regulatory region which resides between positions -919 and -860 relative to the ATG translation initiation codon of the EGF receptor promoter. This 60-base pair region contains a repressor of the EGF receptor promoter and a TGF-beta inhibitory element that mediates TGF-beta 1 suppression of transin/stromelysin gene transcription through binding of a Fos-containing protein complex. Cotransfection of c-fos, c-jun, or both expression vectors with the intact or 5'-deleted ERCAT constructs identified several Fos-responsive inhibitory regions within the EGF receptor promoter, but these did not localize to the -919 to -860 promoter region. Mobility shift assays showed binding of the 60-base pair DNA fragment to proteins in extracts from untreated normal rat kidney cells; the binding was specifically competed by oligonucleotides containing a CAGATG sequence but not by oligonucleotides containing the EGF receptor repressor or the TGF-beta inhibitory element. TGF-beta 1 treatment but not anti-Fos antibody caused a decrease in specific 60-base pair DNA-protein complex formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitric oxide-independent response to acetylcholine by terminal arterioles in rat cremaster muscle

The aim of the present study was to establish whether, in terminal arterioles from the rat cremaster, acetylcholine (ACh) elicits nitric oxide (NO)-independent dilation corresponding to the transient ACh-induced endothelium-dependent hyperpolarization described in arteries. For this purpose, the responses of terminal arterioles [mean diam 15.0 +/- 0.4 (SE) microns] were studied by intravital microscopy in rat cremaster muscle. During 15 min of superfusion by 10(-5) M ACh, the response was characterized by an initial maximal dilation (peak time < 3 min) followed by a more sustained dilation that slightly decreased with time. Inhibition of NO synthesis by 2 x 10(-4) M N omega-nitro-L-arginine (L-NNA) significantly reduced, but did not eliminate, both the peak and sustained responses. Simultaneous administration of 2 x 10(-4) M L-NNA and 2 x 10(-5) M mefenamic acid, an inhibitor of prostaglandin synthesis, did not induce a significantly different response from that observed with L-NNA alone. Procaine (10(-3) M), which is known to inhibit completely ACh-induced hyperpolarization in carotid artery, drastically reduced the initial part of the ACh-induced dilation but not the sustained response. Simultaneous administration of procaine and L-NNA almost completely inhibited the peak response to ACh. Similar results were obtained when L-NNA was combined with a superfusion bath containing 20 mM KCl, a concentration known to reduce hyperpolarization in arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Local renin-angiotensin system in the microcirculation of spontaneously hypertensive rats

We studied the local renin-angiotensin system in the microcirculation of cremaster muscle in spontaneously hypertensive rats (SHR) and their normotensive Wistar-Kyoto (WKY) controls. We used intravital microscopy in an original preparation of cremaster isolated from its normal blood supply and externally perfused with physiological solution, thus allowing the exclusion of circulating converting enzyme, circulating renin, and circulating angiotensinogen. We classified arterioles studied as second-, third-, and fourth-order, with mean diameters, respectively, of 67 +/- 6, 35 +/- 2, and 17 +/- 1 microns in WKY controls and 61 +/- 5, 34 +/- 2, and 16 +/- 1 microns in SHR. No difference between WKY controls and SHR was found for arteriolar vasoconstrictions in response to topical administration of 0.01 to 1 nmol/mL angiotensin II. Conversely, in response to 0.01 to 1 nmol/mL angiotensin I, significantly more arteriolar vasoconstriction was found in SHR cremaster muscle. In both strains, responses to angiotensin I were significantly inhibited by 10 nmol/mL of the angiotensin-converting enzyme inhibitor lisinopril. When angiotensinogen-rich, renin-free plasma containing 2.3 nmol/mL angiotensinogen was administered, almost no vasoconstriction was found in WKY controls, but significant constrictions were observed in SHR (23 +/- 4%, 30 +/- 5%, and 41 +/- 4% for second-, third-, and fourth-order arterioles, respectively). In SHR, vasoconstriction in response to angiotensinogen-rich, renin-free plasma was dose dependent, was inhibited by lisinopril, and was not found 24 hours after bilateral nephrectomy. Topical administration of 1.2 micrograms/mL renin did not induce arteriolar vasoconstriction in either WKY or SHR cremaster muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Functionally important amino acids in the TCR revealed by immunoselection of membrane TCR-negative T cells

A spontaneous TCR cell surface variant (3P11) of the Jurkat T cell line is described and characterized. 3P11 was selected by incubation of Jurkat cells with anti-TCR mAb followed by passage through Ig anti-Ig columns and cloning. 3P11 contained mRNA for both Ti alpha and Ti beta and CD3 gamma, delta, epsilon and zeta. Biochemical analyses demonstrated that all of the TCR components were produced in 3P11 cells. The Ti alpha beta/CD3 gamma delta epsilon zeta complex was assembled in the endoplasmic reticulum but the zeta did not associate with this complex. Epitopes recognized by the Ti beta chain specific mAb beta F1 and JOVI as well as anti-V beta 8 were affected in the 3P11 Ti beta chain indicating that the 3P11 Ti beta chain was mutated. Transfection of a wild-type Ti beta cDNA into 3P11 cells reconstituted TCR expression. Sequence analyses of the 3P11 Ti beta chain demonstrated a guanine to adenine change in the second nucleotide of the triplet coding for cysteine191 resulting in a cysteine to tyrosine exchange. Cysteine191 is the C-terminal cysteine involved in the intrachain disulfide bond in the C domain of the Ti beta chain; thus, the 3P11 Ti beta chain did not contain this disulfide bond. Transfection of a site-directed Ti beta chain containing the 3P11 mutation into a Ti beta negative variant of the Jurkat cell line resulted in a TCR phenotype identical with 3P11 demonstrating that the mutation identified in the 3P11 Ti beta chain was the sole cause for the 3P11 defect.

Functionally important amino acids in the TCR revealed by immunoselection of membrane TCR-negative T cells

A spontaneous TCR cell surface variant (3P11) of the Jurkat T cell line is described and characterized. 3P11 was selected by incubation of Jurkat cells with anti-TCR mAb followed by passage through Ig anti-Ig columns and cloning. 3P11 contained mRNA for both Ti alpha and Ti beta and CD3 gamma, delta, epsilon and zeta. Biochemical analyses demonstrated that all of the TCR components were produced in 3P11 cells. The Ti alpha beta/CD3 gamma delta epsilon zeta complex was assembled in the endoplasmic reticulum but the zeta did not associate with this complex. Epitopes recognized by the Ti beta chain specific mAb beta F1 and JOVI as well as anti-V beta 8 were affected in the 3P11 Ti beta chain indicating that the 3P11 Ti beta chain was mutated. Transfection of a wild-type Ti beta cDNA into 3P11 cells reconstituted TCR expression. Sequence analyses of the 3P11 Ti beta chain demonstrated a guanine to adenine change in the second nucleotide of the triplet coding for cysteine191 resulting in a cysteine to tyrosine exchange. Cysteine191 is the C-terminal cysteine involved in the intrachain disulfide bond in the C domain of the Ti beta chain; thus, the 3P11 Ti beta chain did not contain this disulfide bond. Transfection of a site-directed Ti beta chain containing the 3P11 mutation into a Ti beta negative variant of the Jurkat cell line resulted in a TCR phenotype identical with 3P11 demonstrating that the mutation identified in the 3P11 Ti beta chain was the sole cause for the 3P11 defect.

CD3 gamma contains a phosphoserine-dependent di-leucine motif involved in down-regulation of the T cell receptor

Several cell surface receptors including the T cell receptor (TCR) are phosphorylated and down-regulated following activation of protein kinase C (PKC). Among other substrates the activated PKC in T cells phosphorylates the CD3 gamma subunit of the TCR. To investigate the role of CD3 gamma phosphorylation in PKC-mediated TCR down-regulation, point mutated CD3 gamma cDNA was transfected into the CD3 gamma-negative T cell line JGN and CD3 gamma transfectants were analysed. Phosphorylation at S126 but not S123 in the cytoplasmic tail of CD3 gamma was required for PKC-mediated down-regulation of the TCR. Furthermore, analysis of a series of CD3 gamma truncation mutants indicated that in addition to S126 phosphorylation a motif C-terminal of S126 was required for TCR down-regulation. Point mutation analyses confirmed this observation and demonstrated that a membrane-proximal di-leucine motif (L131 and L132) in the cytoplasmic tail of CD3 gamma was required for PKC-mediated TCR down-regulation in addition to phosphorylation at S126. Incubation of T cells in hypertonic medium known to disrupt normal clathrin lattices severely inhibited PKC-mediated TCR down-regulation in non-mutated T cells, indicating that the TCR was down-regulated by endocytosis via clathrin coated pits. Based on the present results and previously published observations on intracellular receptor sorting, a general model for intracellular sorting of receptors containing di-leucine- or tyrosine-based motifs is proposed.

Structure of the T cell receptor in a Ti alpha V beta 2, alpha V beta 8-positive T cell line

The T cell receptor (TcR) is composed of at least six different polypeptide chains consisting of the clonotypic Ti heterodimer (Ti alpha beta or Ti gamma delta) and the noncovalently associated CD3 chains (CD3 gamma delta epsilon zeta). The exact number of subunits constituting the TcR is still not known; however, it has been suggested that each TcR contains two Ti dimers. To gain insight into the structure of the TcR we constructed a Ti alpha V beta 2, alpha V beta 8-positive T cell line which expressed the endogenous human TiV beta 8 and the transfected mouse TiV beta 2 both in association with the endogenous Ti alpha and CD3 chains at the cell surface. Preclearing experiments with radioiodinated cell lysate prepared with digitonin lysis buffer demonstrated that depleting the lysate of Ti alpha V beta 8 by immunoprecipitation with anti V beta 8 monoclonal antibody (mAb) did not reduce the amount of Ti alpha V beta 2 in the lysate, and likewise, depleting the lysate of Ti alpha V beta with anti-V beta 2 mAb did not reduce the amount of Ti alpha V beta 8. Comodulation experiments showed that V beta 8 and V beta 2 did not comodulate with each other. Furthermore, functional tests demonstrated that TcR containing V beta 8 and TcR containing V beta 2 mediated transmembrane activation signals independently of each other. These data demonstrate that mouse V beta 2 and human V beta 8 were not expressed in the same TcR in agreement with a TcR model where each TcR contains only one Ti dimer.