Investigation of plasma membrane-associated apolipoprotein E in primary macrophages

Our previous studies identified the lysosome as the compartment for degradation of newly synthesized apoE in primary macrophages. Lysosomal degradation of newly synthesized apoE is extensive and rapid (> 50% in 60 min). In the present study we tested the hypothesis that the macrophage cell surface is part of the itinerary of apoE in its path to the lysosomes. We therefore examined the existence and size of the apoE pool associated with the macrophage cell surface. Such a pool may not only provide a mechanism of targeting apoE for lysosomal degradation, by endocytosis, but also have important implications for the metabolism of lipoproteins by macrophages. Treatment of macrophages with heparin (10 micrograms/ml and 5 mg/ml) and heparinase I (1 U/ml), which releases substantial amounts of apoE from HepG2 cells, results in no additional release of apoE from macrophages. Treatment of macrophages with xyloside (1 mM) or GRGDTP (500 micrograms/ml) does not decrease the extent of cell-associated apoE. Both immunogold labeling, followed by electron microscopy, and immunofluorescent labeling and light microscopy further confirm the lack of significant amounts of cell surface-associated apoE in macrophages. In contrast, immunolabeled apoE is readily observed in permeabilized cells. Taken together, these data indicate the absence of significant apoE-glycosaminoglycan interaction at the macrophage cell surface. The lack of such an interaction is likely due to paucity of heparan sulfate proteoglycans on the macrophage cell surface, when compared to hepatocytes. Along with our previous observations. (Deng. J., V. Rudick, and L. Dory, 1995. J. Lipid Res. 36:2129-2140), these results suggest direct targeting of a portion of newly synthesized apoE from trans-Golgi network to lysosomes for degradation, without involving the plasma membrane and endocytosis.

Amphotericin B enzyme-linked immunoassay for clinical use: comparison with bioassay and HPLC

OBJECTIVE

To evaluate a new enzyme-linked immunosorbent assay (ELISA) for amphotericin B in serum samples. Results are compared with those obtained by HPLC and bioassay.

DESIGN

Comparison of results obtained by ELISA, HPLC, and bioassay.

METHODS

We developed a new ELISA using a polyclonal rabbit antibody to measure serum amphotericin B concentrations. Blinded samples of amphotericin B in concentrations of 0.15-78 micrograms/mL were prepared in human serum and assayed simultaneously by the ELISA, HPLC, and bioassay. The results of each assay were derived from standard curves and evaluated by using the Table Curve 2D computer program. These data were compared by using correlation analysis with evaluation of Pearson's correlation coefficient by Student's t-test.

RESULTS

ELISA and bioassay compared favorably at amphotericin B concentrations of 0.3-20 micrograms/mL with a correlation coefficient of r = 0.993, while ELISA and HPLC compared with a correlation coefficient of r = 0.944. The average coefficient of variation over the range 0.3-20.0 micrograms/mL was 28% +/- 7% for HPLC, 26% +/- 9% for ELISA, and 13% +/- 4% for bioassay. Comparison of all three assays revealed the highest correlation with the ELISA assay (r = 0.998) for the range of concentrations (0.3-20 micrograms/mL) routinely achieved. Samples containing concentrations in excess of 20 micrograms/mL could be diluted. Desiccation for concentrations less than 0.3 microgram/mL was not tested.

CONCLUSION

The determination of serum amphotericin B concentrations by ELISA gave results similar to those obtained by a bioassay and HPLC technique. Although variability appears greater with ELISA, the ease of performing yjis assay expedites the evaluation of amphotericin B concentrations from lipid formulations without interference from coadministered antibacterials of azole antifungals.

The role of calcium ion in the pathogenesis of human pituitary GH-secreting adenomas

To study the role of Ca2+ in the pathogenesis of pituitary growth hormone secreting adenomas, the function of Ca2+ in 23 cases of human pituitary GH-secreting adenoma was investigated in monolayer cell culture. It was found that Ca2+ channel blockers nicardipin and nifedipin inhibited basal and growth hormone releasing hormone (GRH)-stimulated GH secretion in 87.5% and 100.0% of the GH adenomas, respectively, demonstrating that in most human pituitary GH adenomas, the basal and GRH regulated GH secretion is Ca2+ dependent. The GRH and sometostatin (SRIF) agonist octreotide regulated the processes of GH secretion via Ca2+ had defects in different steps including receptor, postreceptor Ca2+ channel and Ca(2+)-GH secreting coupling in 6(66.6%) and 5(55.5%) cases of 9 GH adenomas respectively. Among them, the defects in GRH receptor and SRIF regulated Ca2+ channel are the main causes of the dysfunction of GH adenomas. These defects may be related to GH hypersecretion in GH adenomas. Our data provides advance evidences for intrinsic defects of GH adenomas.

Three-dimensional magnetic resonance imaging of the postmortem fetal heart

Five postmortem fetuses were scanned by magnetic resonance (MR) imaging. Of eight three-dimensional (3D) data sets reconstructed on an MGI workstation, five sets demonstrated detailed 3D fetal cardiac structures, and one depicted clear information regarding the disposition and compression of the heart and lungs in diaphragmatic hernia. This study has shown the potential of 3D MR imaging in support of postmortem examination and for interactive visual teaching of the fetal cardiac structures. The new technique may eventually be of significance in prenatal detection of cardiac abnormalities with the development of fast real-time MR imaging.

Hydrogen peroxide sensor based on coimmobilized methylene green and horseradish peroxidase in the same montmorillonite-modified bovine serum albumin-glutaraldehyde matrix on a glassy carbon electrode surface

A new approach to construct a second-generation amperometric biosensor is described. The classical dye methylene green as a probing-needle mediator and horseradish peroxidase as a base enzyme were coimmobilized in the same montmorillonite-modified bovine serum albumin (BSA)-glutaraldehyde matrix to construct a H2O2 sensor. The immobilization matrix was formed from the pretreated sodium montmorillonite colloid in which the enzyme and the cross-linker were dissolved. Immobilization of methylene green from the dye mother solution was attributed to the adsorption function of the montmorillonite, whereas immobilization of horseradish peroxidase was attributed to the cross-linking function of the BSA-glutaraldehyde as usual. Cyclic voltammetry and potentiostatic measurements indicated that methylene green efficiently mediated electrons from the base electrode to the enzyme in the matrix. The sensor responded rapidly to low H2O2 concentration and achieved 95% of the steady-state current in less than 20 s, with a detection limit of 4.0 x 10(-7) M H2O2.

[Detecting immunoreactive GH mRNA in human peripheral blood lymphocytes]

The present study demonstrats that immunoreactive GH mRNA is expressed at low level in normal human peripheral blood lymphocytes by RT-PCR amplification and hybridization. Northern blot analysis of total RNA from lymphocytes with a pituitary hGH cDNA probe revealed a faint transcript migrating almost coincident with pituitary hGH menssenger RNA. Reverse transcription-polymerase chain reaction from total RNA of lymphocytes by using hGH specific primers generated a predicted 702 base pair band with almost the same size as pituitary and also hybridized with pituitary hGH cDNA probe specifically in Southern blot analysis, which indicates a low level expression of GH-like mRNA in human peripheral blood lymphocytes.

The role of GRH mediated AC-cAMP system in the pathogenesis of human pituitary GH-secreting adenomas

OBJECTIVE

To investigate the role of AC-cAMP system in the transmission of the action of the growth hormone releasing hormone (GRH) on growth hormone (GH) release in pituitary GH-secreting adenomas.

METHODS

The effects of GRH (10(-7) mol/L) on intracellular cAMP levels and GH release and the effects of AC-cAMP stimulators, cholera toxin (Ct, 50 micrograms/L), forskolin (10(-5) ml/L) and db-cAMP (10(-3) mol/L) on GH secretion were studied in cultured cells of 21 GH-secreting adenomas obtained from operation for acromegalic patients.

RESULTS

GRH and Ct failed to stimulate GH secretion in 61.9% (13/21 cases) and 57.1% (12/21 cases) pituitary GH adenoma cell cultures respectively. Forskolin stimulated GH release in 88.9% (8/9 cases), while db-cAMP induced GH secretion in all cases tested (5/5 cases). The intracellular cAMP levels were elevated by GRH in the 4 out of 9 cases of tumor cell cultures, but not in the other 5 cases. According to the GH secretory responses to GRH and Ct, the 21 GH tumors were divided into 4 groups. In group A and B, GRH can stimulate GH release, but Ct has stimulative role only in group A. In group C and D, GRH fails to stimulate GH secretion. However group A can respond to Ct, but group D has no response.

CONCLUSIONS

The GH hypersecretion in most acromegalic patients is mainly due to the defects of pituitary adenoma cells, especially the abnormalities of GRH receptor and/or stimulative guanosine protein.

An amperometric new methylene blue N-mediating sensor for hydrogen peroxide based on regenerated silk fibroin as an immobilization matrix for peroxidase

A simple and effective procedure was described for the immobilization of peroxidase in regenerated silk fibroin membrane prepared from waste silk. The membranes of regenerated silk fibroin with or without peroxidase, before or after the ethanol treatment, were characterized by ir spectra. An amperometric H202 sensor, based on the immobilized peroxidase in regenerated silk fibroin membrane, in the use of new methylene blue N as an electron transfer mediator, was fabricated. The characteristics of the sensor with respect to linearity, response time, effect of pH and temperature, stability, and reproducibility were investigated. Dependences of Michaelis-Menten constant KMapp on the concentration of the mediator, and the applied potential were also studied and the results were presented. The sensor was highly sensitive to H2O2 with a detection limit of 1.0 x 10(-7)M and with response time of less than 40 s.

Entrapment of both glucose oxidase and peroxidase in regenerated silk fibroin membrane

Two enzmyes, glucose oxidase and peroxidase, were for the first time simultaneously immobilized in regenerated silk fibroin membrane. The structure and morphology of the regenerated silk fibroin membrane containing both glucose oxidase and peroxidase were investigated with IR spectra and SEM. The bienzymes do not change the structures of the regenerated silk fibroin in the membrane, which has an islands-sea structure. For the first time, an amperometric methylene green mediating sensor for glucose based on co-immobilization of both glucose oxidase and peroxidase in regenerated silk fibroin was constructed. Cyclic voltammetry and amperometry were used to test the suitability of methylene green shuttling electrons between peroxidase and the glassy carbon electrode. The bienzyme-based system offers fast response and high sensitivity of the sensor to glucose. The effects of pH, temperature, and the concentration of the mediator on the response current were evaluated, and the dependence of the Michaelis-Menten constant K(m)(app) on the concentration of the mediator was investigated.

Amphotericin B enzyme-linked immunosorbent assay

Our purpose was to develop and characterize an enzyme-linked immunosorbent assay (ELISA) which could measure the concentration of amphotericin B in serum. Amphotericin B was assayed by competition ELISA. Multiwell ELISA plates coated with amphotericin B (1.0 micrograms/ml) conjugated to bovine serum albumin were used to test replicates of serum samples spiked with amphotericin B. Purified rabbit polyclonal antibody against amphotericin B (1.4 micrograms/ml) was added subsequent to the instillation of samples spiked with unknown amounts of amphotericin B. Experiments were performed to test the sensitivity, specificity, precision, and accuracy of the assay. The ability to measure lipid-associated amphotericin B was also evaluated in preliminary studies. Analysis of reference samples containing amphotericin B yielded a traditional sigmoidal curve. The limits of detection were 0.15 to 156 micrograms/ml. The sensitivity of the assay was affected by light and temperature exposure. Assay specificity was altered only by the presence of nystatin, a polyene antifungal agent similar to amphotericin B. Intrarun (coefficient of variation = 3.0%) and interrun (coefficient of variation = 12.8%) coefficients of variation were calculated and were comparable to those in similar assays. The assay's correlation coefficient (r = 0.907) demonstrated a statistically significant correlation between the optical density of the sample and the concentration of drug in the sample. The amphotericin B ELISA's ease, precision, and overall accuracy suggest that this assay could be used for assessments of serum amphotericin B concentrations. Multiple research questions concerning the role of serum amphotericin B concentrations in toxicity and efficacy have gone unanswered because of the labor-intensive nature of the assays which have been available to date. The ability to easily and rapidly measure 40 duplicate samples containing amphotericin B should also prove to be a distinct advantage for clinical research or reference laboratories in addressing these questions.

[The role of Ca2+ in the pathogenesis of human pituitary GH-secreting adenomas]

Effects of Ca2+ channel blockers (nicardipin and nifedipin) and Ca2+ ionophore A23187 on the basal secretion and on the secretion stimulated by GRH or inhibited by SMS, a SRIF analogne of GH were investigated in monolayer cell cultures of 23 cases of human pituitary GH-secreting adenomas. The roles of GRH and SMS in 45Ca influx were investigated also. The GH secretion of most GH adenomas was depended on Ca2+, but the abnormality in different link of GH secretion mediated by Ca2+ was observed. The defects of receptor and post-receptor including Ca2+ channel and Ca(2+)-GH secretion couple regulated by GRH and SRIF were found in 66.7% and 55.6% of GH adenomas respectively. These abnormalities may contribute to GH hypersecretion in GH adenomas.

Fetal echocardiography in three and four dimensions

A three-dimensional (3D) acquisition system using an electromagnetic position sensor attached to a standard transducer on an unmodified ultrasound scanner was developed to capture two-dimensional (2D)-fetal echocardiograms at various positions and orientations. Operating in real-time directed M-mode allowed recording of 2D structural images and cardiac motion curves, from which the fetal cardiac phase could be determined. By digitising over 100 image frames for each scanning sequence, and by selecting frames at particular phases, 3D views of the fetal heart were reconstructed for each phase. Of 20 sequences of six fetuses scanned, 13 sequences successfully demonstrated usable 3D fetal heart structures, including four cardiac chambers, ventricular and atrial septa, foramen ovale and some of the cardiac valves and great vessels. Rearrangement of those phased 3D images into a cyclic sequence could generate dynamic 3D views of a beating fetal heart. We believe that, with further technical development, this new approach will be of use in the diagnosis of prenatal cardiac malformations and malfunctions, in in utero cardiac surgery and in fetal cardiology teaching.

Topology of prostaglandin H synthase-1 in the endoplasmic reticulum membrane

Prostaglandin H synthase-1 is an integral endoplasmic reticulum membrane protein which catalyzes a key control step in prostaglandin biosynthesis. The overall arrangement of the prostaglandin H synthase-1 polypeptide with respect to the endoplasmic reticulum membrane was examined in transiently transfected COS-1 cells, using immunofluorescence microscopy. A bacterial toxin, streptolysin-O, was used for selective plasma membrane permeabilization and a detergent, saponin, for general membrane permeabilization. Treated cells were probed with six antibodies specific for particular prostaglandin H synthase-1 peptide segments and one antibody specific for an inserted viral reporter epitope. Control experiments established that actin, a cytoplasmic marker, was accessible to fluorescein-labeled phalloidin after streptolysin-O treatment, whereas antibodies against protein disulfide isomerase, an endoplasmic reticulum lumenal marker, bound only after saponin treatment, Using this approach to investigate prostaglandin H synthase-1, it was found that streptolysin-O treatment was sufficient to obtain staining of intracellular membranes by antibodies specific for the endogenous C-terminal segment, for the viral reporter inserted at the C-terminus, and for the protease-sensitive region near arg277. In contrast, saponin treatment was necessary for staining by antibodies specific for peptides spanning residues 51-66, 156-170, and 377-390. Antibodies targeted against residues 483-496 did not stain transfected cells even after saponin permeabilization, although they did bind to detergent-solubilized prostaglandin H synthase-1. These results indicate that the C-terminus and arg277 regions of the synthase can be exposed on the cytoplasmic side of the endoplasmic reticulum membrane, whereas regions near N-glycosylation sites are confined to the endoplasmic reticulum lumen and residues 483-496 are inaccessible from either side of the endoplasmic reticulum membrane.

Lysosomal degradation and sorting of apolipoprotein E in macrophages

We previously reported that a substantial amount of newly synthesized apoE in mouse macrophages is degraded prior to secretion; a portion of this pool of apoE can be rescued by the addition of HDL3 to the incubation medium. In the present studies, the location and nature of the intracellular degradation of apoE were more closely examined. Inhibitors of protein trafficking (brefeldin A) as well as a number of protease inhibitors were used. The experiments using brefeldin A (5 micrograms/ml) clearly established that neither the endoplasmic reticulum nor the Golgi complex are the sites of apoE degradation. Using a pulse-chase design, [35S]apoE cannot be chased out in the presence of brefeldin A and remains undegraded within the cell. The accumulated apoE lacks the sialic acid residues, indicating that this final stage of processing must occur in the trans-Golgi network or later. Lysosomotropic agents, ammonium chloride and chloroquine, on the other hand, inhibit apoE degradation by over 70 and 80%, respectively, while total cell protein degradation remains unaffected. Similarly, a cocktail consisting of four lysosomal protease inhibitors (pepstatin, E-64, chymostatin, and antipain), inhibits specifically apoE degradation by over 60%. In contrast, ALLN, an inhibitor of Ca(2+)-dependent cysteine proteases, has a moderate effect on apoE degradation (30% inhibition) and a more pronounced effect on total protein degradation. These data suggest that the site of intracellular apoE degradation in the macrophage is the lysosome. These conclusions are supported by light and electron microscopy of macrophages, clearly showing the presence of immunoreactive apoE (along with cathepsin D) in the endosomal/lysosomal compartment of control and lysosomotropic agent-treated cells. In contrast, little or no labeling is seen in this compartment in brefeldin A-treated cells. At lower concentrations of the lysosomotropic agents, the extent of inhibition of apoE degradation is compensated for by its increased secretion, in a manner analogous to the effect of these agents on lysosomal enzymes. Higher concentrations of these agents, which lead to a profound inhibition of apoE degradation, also specifically block apoE secretion. The block in apoE secretion in the presence of high concentrations of chloroquine leads to undiminished or higher concentrations of immunoreactive apoE in the endosomal/lysosomal compartment, suggesting that apoE is targeted for lysosomal degradation directly, without prior secretion or surface association. These data strongly suggest pH-dependent sorting of apoE in macrophages to the degradative and secretory pathways and imply a protein-protein interaction in the process.

[Apoptosis of mouse MS-2 fibrosarcoma cells induced by photodynamic therapy with LDL-administered zinc-phthalocyanine]

Photodynamic destruction of MS-2 fibrosarcoma cells in mice induced by LDL-administered Zinc-phthalocyanine and red light irradiation was studied by electron microscopy. The pronounced structural changes such as chromatin condensation, disappearance of nuclear pores, karyopyknosis, karyorrhexis, leakage of chromatin aggregates, autophagocytosis, bleb formation on the cell surface, cytoplasmic vacuolization and cell fragmentation suggest that the tumor cell death was induced by apoptosis. However, its exact mechanism and regulating pathways remain to be further investigated.

[Analysis of 1116 strains of pathogens isolated from infected burn wounds]

We report the analysis of 1,116 strains of pathogens isolated from infected burn wounds of 536 patients hospitalized from 1989 to 1991. From the 1,116 strains of pathogens, 39 species of aerobes and fungi were found, including 217 strains of staphylococcus aureus, 208 strains of Pseudomonas aeruginosa and 119 strains of Acinetobacter calcoaceticus. The positive rates of the above three bacteria were 19.4%, 18.6% and 10.6% respectively. Some opportunistic pathogens, such as bacillus cercus, aerococcus virdans and aspergillus etc. were also isolated from the burn wounds as well as the ward environments. The drug sensitivity of some of the common bacterial was determined.

Effects of 3,4-dihydroxyacetophenone on hypoxic vasoconstriction in isolated pulmonary and basilar arterial rings

The effects of 3,4-DHAP on hypoxic vasoconstriction response in pulmonary (PA) and basilar arterial (BA) rings of rabbits and their mechanism were compared in vitro. 3,4-DHAP in different concentration (2.64 x 10(-4), 7.92 x 10(-4), 2.376 x 10(-3) mol/L) decreased the basal tone of PA rings by 32.39 +/- 9.4 mg, 68.96 +/- 26.54 mg and 145.60 +/- 58.07 mg respectively, while the tension of the BA rings was decreased by 13.80 +/- 5.08 mg, 17.18 +/- 3.36 mg and 25.00 +/- 4.02 mg respectively. In PA rings it also decreased the percentage increase in tension induced by hypoxia (TIH%) from the control value 48.82 +/- 5.75% to 10.02 +/- 3.62%, 2.14 +/- 0.96%, and 0.00% respectively, while in BA rings from 27.27 +/- 5.78% to 11.23 +/- 2.71%, 7.49 +/- 1.62%, and 1.45 +/- 1.13% respectively. The effects of 3, 4-DHAP on TIH% were partially blocked by indomethacin 10 M and L-NAME 10 M. The results showed that 3, 4-DHAP can decrease the hypoxic pulmonary and basilar vasoconstriction in vitro, which can be partially inhibited by cyclooxygenase inhibitor and NO/EDRF inhibitor.

Soleus muscle contractile properties in hypertensive rats

Three types of hypertensive rats, and their normotensive controls, were assessed to determine the effects of high blood pressure on the contractile and fatigue properties of the soleus muscle. Spontaneously hypertensive rat (SHR) soleus developed less contractile force and fatigued more rapidly than normotensive Wistar-Kyoto (WKY) controls. In contrast, normotensive Wistar and Wistar-1 kidney/1 renal clip hypertensives were similar in their responses, and Dahl salt-sensitive hypertensives and Dahl salt-resistant controls also did not exhibit any significant differences in tension development or endurance. The results suggest that the decreased ability to develop force and maintain it during stimulation may not be directly related to the high blood pressure in SHR. It may instead be related to a gene defect that cosegregates with the loci responsible for the rise in blood pressure. The reduced endurance in SHR may be associated with an increased accumulation of K+ in the muscle during contraction, which decreases performance. It may also decrease the ability of the vessels to dilate during muscle contraction, preventing maintenance of an adequate blood supply.

Pulsed-laser-induced dark traces in LiNbO(3):Zn and LiNbO(3):Mg

Laser-induced dark traces in LiNbO(3):Zn (7.5 mol.%) and LiNbO(3):Mg (6.5 mol.%) crystals have been studied with the crystals as the component for 1064-532-nm second-harmonic generation of Nd:YAG radiation operating in a pulsed mode. The results show that, at high input power density, both crystals suffer from dark traces, which reduce the second-harmonic-generation efficiency. The dark traces are induced by the 532-nm radiation and can be recovered after the laser beam is shut off. The transmission loss spectra show a broad absorption peak near 400 nm.

Effect of intracerebroventricular injection of 6-hydroxydopamine on the peripheral catecholamine and angiotensin II in SHR

This investigation revealed that the contents of A II and NE in plasma, heart and aorta and E content in plasma were significantly increased in SHR at the age of 12th week. At the same time the systolic blood pressure of SHR was much higher than that of the age-matched WKY. The intracerebroventricular administration of 6-OHDA in SHR at the age of 8th week not only prevented the development of hypertension, but also reduced the contents of NE and E in the brain regions, heart, aorta and plasma. Simultaneously A II content in heart, aorta and plasma was decreased. These results suggested that: 1. the renin-angiotensin system and peripheral sympatho-adrenal system are overactive in SHR, 2. the overactivity of peripheral sympatho-adrenal system is dependent on the central catecholaminergic neurons, and 3. the action of sympatho-adrenal system is partly responsible for the increase of A II content in plasma, heart and aorta in SHR.

[Effects of 1,25-(OH)2D3 on the secretion of growth hormone by human pituitary growth hormone-secreting tumors in vitro]

This work studied the effects of 1,25-(OH)2D3 on the secretion of growth hormone (GH) in 15 cases of human pituitary GH-secreting tumor cell cultures. At physiological doses (40-80 pg/ml) of 1,25-(OH)2D3, a GH secretion response was found in 14 cases of pituitary tumor: GH secretion was suppressed significantly in 9 of 14 cases and was markedly stimulated in only 2 of 14 cases of pituitary tumors. In the other 3 cases, the GH response was variable at different days of culture. The degree of suppression of GH secretion induced by 1,25-(OH)2D3 in all cases was 63.1 +/- 3.3% (means +/- sx of the control, and the average increase of GH secretion was 164.0 +/- 6.2% of control. There was no correlation between the type of GH reaction and the dose rang of 1,25-(OH)2D3 used in the experiment. The stimulatory effect on GH secretion did not appear after 2 weeks of culture. The results demonstrate that 1,25-(OH)2D3 at physiological doses has a direct regulatory effect (mainly suppressive) on GH secretion in most pituitary GH-secreting tumors in cell culture.

[Echocardiographic detection of fetal cardiac arrhythmias]

Using real-time directed M-mode and Doppler echocardiography we identified cardiac arrhythmias in 10 fetuses. One had signal tachycardia, one bradycardia, 5 supraventricular premature contractions, and 2 ventricular premature contractions (VPC), which were all self-limited. The diagnosis of VPC in one case was based on premature ending of foramen ovale flap's 2 nd wave on M-mode recording. All cases carried a favorable prognosis except the one with VPC who had a small ventricular septal defect overlooked prenatally. The 10 th case had II degrees atrioventricular block complicated by heart failure and died in utero. This study showed that most arrhythmias can be detected antenatally by analysing atrioventricular contraction sequences. It also proved that the characteristic M-mode pattern of foramen ovale flap is of value in evaluating the types of arrhythmias.

[Effect of dopamine and bromocriptine on secretion of growth hormone by pituitary growth hormone secreting tumor in cell culture]

This article reports the effect of dopamine (DA) and its agonist bromocriptine (CB154) on the secretion of growth hormone (GH) by pure GH-secreting pituitary tumor in cell culture as well as a comparison of the effects of these dopaminergic drugs and SMS201-295 (SMS). DA of 10(-8) and 10(-7) mol/L reduced GH secretion to 50.6 and 44.4% of the control, respectively, in 1 out of 6 tumors. CB154 of 10(-7) and 10(-6) mol/L suppressed GH secretion to 59.0 +/- 8.9% of the control in 3 out of 4 tumors. CB154 was at least 10 times less potent than SMS vis a vis GH secretion. CB154 of 10(-6) mol/L inhibited GH secretion to 63.3 +/- 13. 8% (n = 4), but SMS of 10(-7) mol/L induced GH secretion to 45.5 +/- 13.1% (n = 4), the concentration difference between CB154 and SMS was 10 times. CB154 suppressed not only GH secretion, but also GH synthesis in two tumor cell cultures. The major role of SMS in GH secretion was inhibition. The results suggest that DA and CB154 have direct inhibitory effects on GH secretion, at least in some pure pituitary GH secreting tumors. The activities of DA and CB154 are not entirely the same as that of SMS.

[Effect of the overactivated central renin-angiotensin system on the concentration of brain norepinephrine and epinephrine in stroke-prone spontaneously hypertensive rats and its significances]

The content of norepinephrine (NE) and epinephrine (E) in the brain of spontaneously hypertensive rats has proved abnormal, but the cause remained unknown. It was shown in the recent work that NE content in pons, posterior hypothalamus, nucleus caudatus and E concentration in medulla oblongata, anterior and posterior hypothalamus of 12-week old stroke-prone spontaneously hypertensive rats (SHRSP) were much higher than those of age-matched Wister-Kyoto rats (WKY). SHRSP also showed higher levels of systolic blood pressure (SBP) and brain angiotensin II (A II) than WKY. Intracerebroventricular (icv) perfusion of angiotensin-converting enzyme inhibitor captopril (20 micrograms for each time and three times for each day for four weeks) inhibited the synthesis of brain A II and reduced SBP and NE, E contents in all examined brain areas in SHRSP and WKY. However, the effects of chronically perfused captopril on SBP and brain NE, E levels in SHRSP were much more significant than in WKY. The results indicate that the modulatory effects of central renin-angiotensin system (RAS) on central adrenergic and noradrenergic system might be overactivated in SHRSP, which might partially responsible for the abnormally high levels of NE, E in some of the brain areas of SHRSP.

[Preliminary studies on the relationship between the blood pressure and renin-angiotensin system in brain and blood vessels in SHRSP]

This work analyzed the relationship between A I concentration in aorta tissue and systolic blood pressure (SBP) in stroke-prone spontaneously hypertensive rats (SHRSP) at different ages. The SBP of SHRSP increased progressively with the age until the age of 20 weeks, when the SBP of SHRSP no longer elevated but sustained at a relatively high and stable level. The A I concentration in aorta of SHRSP was much higher than that of Wistar Kyoto rats at all of the three different ages. Perfusion of captopril into the lateral cerebroventricle of SHRSP for four weeks evoked a considerable decrease of A I concentration in brain as well as a significant reduction of SBP accompanied by a decrement of A I concentration in aorta and concentration of norepinephrine and epinephrine in aorta tissue and plasma. The results further confirm the close relationship between the changed activity of renin-angiotensin system localized in blood vessels during hypertension and the pathogenesis of hypertension, and indicate the possible regulative control of A I generated from central nervous system over the production of A I from blood vessels by means of facilitating the activity of peripheral sympathetic nerve system.

[Pathologic and radiologic study of parosteal osteosarcoma. Report of 17 cases]

17 cases of parosteal osteosarcoma (POS) were studied radiologically and pathologically. It was found that the differentiation of the tumor component in the narrow basic area was the poorest and the surrounding part was the next. The tumor has the tendency to invade the cortex and then infiltrate the surrounding soft tissues in the early stage of tumor formation at the narrow basic area. We have summed up four types of essential X-ray features of cortical erosion and their pathological bases, clarified the limited ability of X-ray to reveal early cortical invasion and the range of infiltration. It seems that POS has the tendency of dedifferentiation on the whole, not being limited in one subtype.

[Analysis of residue and regression of metastatic cervical lymph nodes in NPC after radiotherapy]

Follow up results of residue and regression of metastatic cervical lymph nodes in NPC after radiotherapy are presented. All the 453 cases have been followed for more than five years. According to WHO's criteria, the relative 5 year survival rate was 43.9%. 389 of 453 had had lymph node metastases in the neck at the beginning of treatment. At the end of radiation, immediate regression rate of lymph nodes was 53.2%, which was related to lymph node size before radiotherapy. Five year survival rate of those whose lymph node metastases disappeared completely was 48.8% (group 1). There were 182 cases with residual nodes at the conclusion of radiation (140 recorded in detail). The regression rate of nodes was 96.4% (135/140) and the 5 year survival rate of these 140 patients was 40.0% (group 2). There is no significant difference and the long term results are similar in the two groups. Total recurrence rate in the neck was 4.4%: 5.3% in group 1 and 3.8% in group 2 (P greater than 0.05). The treatment results of the local cervical lesions are the same, too. In 182 cases with residual lesions, 121 with 147 clinically evaluable residual nodes, 0.5 approximately 3 cm in diameter, were followed. The regression time of these residual nodes was 2.5 approximately 2.7 months as to geometric mean (the regressive confidence limit 95%). To sum up, according to the routine cervical target dose, some nodes remaining at the of radiation seem to require no boost dose in order to avoid delayed radiation complications. But the residual nodes which recur during follow up would require a prompt retreatment.