X region deletion variants of hepatitis B virus in surface antigen-negative infections and non-A, non-B hepatitis

The etiology of non-A, non-B hepatitis (NANBH) in renal dialysis patients was determined. Hepatitis C virus was present in many, but its appearance did not correlate with elevated alanine aminotransaminase. When sera from these patients were tested for antibodies against hepatitis B virus (HBV) X antigen and polymerase, 70% were positive. HBV infection was confirmed by polymerase chain reaction using several HBV-specific primer pairs. However, amplification with X region primers failed to yield products in many patients. Cloning and sequencing of these products demonstrated deletions within the X region. Hence, X-deletion variants of HBV are strongly associated with NANBH in renal dialysis patients.

Characterization of benzo[a]pyrene metabolism and related cytochrome P-450 isozymes in Syrian hamster livers

Cytochrome P-450 monooxygenases of golden Syrian hamsters were characterized with respect to benzo[a]pyrene metabolism. Male hamsters were treated with phenobarbital, 3-methylcholanthrene, dexamethasone, benzoflavone, or ethanol, and the activity of aryl hydrocarbon hydroxylase and benzo[a]pyrene activation was determined by mutagenicity testing in hepatic microsomes. Aryl hydrocarbon hydroxylase activity was induced markedly by treatment with phenobarbital but not with 3-methylcholanthrene, nor with other chemicals. The degree of benzo[a]pyrene activation on mutagenicity testing was significantly elevated by treatment with 3-methylcholanthrene and phenobarbital but was reduced with dexamethasone. Immunoinhibition of these activities and Western blotting of hepatic microsomes using antibodies against cytochrome P-450 isozymes suggested that the isozymes responsible for benzo[a]pyrene metabolism in Syrian hamsters belong to the CYP1A, CYP2A, and CYP3A families, a result that differs from observations in rats.

Studies on the catalytic mechanism of five DNA glycosylases. Probing for enzyme-DNA imino intermediates

DNA glycosylases catalyze scission of the N-glycosylic bond linking a damaged base to the DNA sugar phosphate backbone. Some of these enzymes carry out a concomitant abasic (apyrimidinic/apurinic(AP)) lyase reaction at a rate approximately equal to that of the glycosylase step. As a generalization of the mechanism described for T4 endonuclease V, a repair glycosylase/AP lyase that is specific for ultraviolet light-induced cis-syn pyrimidine dimers, a hypothesis concerning the mechanism of these repair glycosylases has been proposed. This hypothesis describes the initial action of all DNA glycosylases as a nucleophilic attack at the sugar C-1' of the damaged base nucleoside, resulting in scission of the N-glycosylic bond. It is proposed that the enzymes that are only glycosylases differ in the chemical nature of the attacking nucleophile from the glycosylase/AP lyases. Those DNA glycosylases, which carry out the AP lyase reaction at a rate approximately equal to the glycosylase step, are proposed to use an amino group as the nucleophile, resulting in an imino enzyme-DNA intermediate. The simple glycosylases, lacking the concomitant AP lyase activity, are propose to use some nucleophile from the medium, e.g. an activated water molecule. This paper reports experimental tests of this hypothesis using five representative enzymes, and these data are consistent with this hypothesis.

[The experimental observation on the procedure of atherosclerotic restenosis following PTCA]

Angioplasty of stenotic iliac artery was performed in 23 Japanese white rabbits. Angiography and histopathology examinations were performed one day (6 rabbits), 3 days (5 rabbits), one week (5 rabbits) and one month (7 rabbits) after dilation. TXB/PGF in blood was analyzed with radio-immunologic method. TXB/6-K-PGF increased at 1st day, began to reduce at 3rd day, became almost normal after one week and returned to normal level week after one month. Restenosis occurred in all animals. Platelet aggregation and mural thrombi were observed at 1st and 3rd day. New endothelial cells covered the surface of denuded endothelium at 3rd day. At 7th day, repairing of endothelium was completed and proliferation of smooth muscle cells were prominent in new intimia. Stenosis of lumen occurred again after 1 month. The results suggested that intimia injury during the procedure initiates the process of restenosis and aggregation of platelets, imbalance of between TXA and PGI is and proliferation of smooth muscle cells play important roles in the formation of restenosis.

Characterization of nervana, a Drosophila melanogaster neuron-specific glycoprotein antigen recognized by anti-horseradish peroxidase antibodies

Antibodies to the plant glycoprotein horseradish peroxidase (HRP) are used extensively to identify neurons in Drosophila and other insects. We are interested in characterizing the gene product(s) recognized by anti-HRP antibodies because it may be important for nervous system function and/or development. Here we identify and purify from adult Drosophila heads an anti-HRP-reactive Mr 42K glycoprotein that is likely to be the major contributor to neuronal specific anti-HRP staining. Several different monoclonal antibodies to the purified 42K glycoprotein recognize up to three proteins with distinct mobilities between Mr 38K and 42K that vary as a function of developmental age. We have collectively named these components Nervana (nerve antigen), because the monoclonal antibodies also specifically stain cultured neurons and embryonic nervous system with a pattern indistinguishable from anti-HRP staining. Western blots indicate the presence of immunologically similar proteins in a wide variety of insect species and in nac (neurally altered carbohydrate) mutant Drosophila flies that lack anti-HRP staining in adult nervous system. It should now be possible to undertake a full biochemical and functional characterization of Nervana in Drosophila.

Two Drosophila nervous system antigens, Nervana 1 and 2, are homologous to the beta subunit of Na+,K(+)-ATPase

A nervous system-specific glycoprotein antigen from adult Drosophila heads, designated Nervana (Nrv), has been purified on the basis of reactivity of its carbohydrate epitope(s) with anti-horseradish peroxidase (HRP) antibodies that are specific markers for Drosophila neurons. Anti-Nrv monoclonal antibodies (mAbs), specific for the protein moiety of Nrv, were used to screen a Drosophila embryo cDNA expression library. Three cDNA clones (designated Nrv1, Nrv2.1, and Nrv2.2) were isolated that code for proteins recognized by anti-Nrv mAbs on Western blots. DNA sequencing and Southern blot analyses established that the cDNA clones are derived from two different genes. In situ hybridization to Drosophila polytene chromosomes showed that the cDNA clones map to the third chromosome near 92C-D. Nrv1 and Nrv2.1/2.2 have open reading frames of 309 and 322/323 amino acids, respectively, and they are 43.4% identical at the amino acid level. The proteins deduced from these clones exhibit significant homology in both primary sequence and predicted topology to the beta subunit of Na+,K(+)-ATPase. Immunoaffinity-purified Nrv is associated with a protein (M(r) 100,000) recognized on Western blots by anti-ATPase alpha-subunit mAb. Our results suggest that the Drosophila nervous system-specific antigens Nrv1 and -2 are neuronal forms of the beta subunit of Na+,K(+)-ATPase.

[Influence of PGE2 on the oxidative modification of LDL and the scavenger receptor activities of macrophages]

The influence of oxidized LDL (OX-LDL) on scavenger receptor of macrophages and the protective effects of PGE2 and selenium was studied by means of BA-ELISA technique, immunohistochemical methods and oil red O histochemistry. The results indicated that the scavenger receptor activities of macrophages in two treated groups were much lower than that of OX-LDL group. Oil red O staining showed that the macrophages in OX-LDL group were full of fatty drops and became foam cells while little lipid could be found in the treated groups. Immunohistochemical study revealed that the entry of OX-LDL into the macrophages was by way of scavenger receptors. The results confirmed that both PGE2 and selenium had marked antioxidizing effects and that PGE2 was slightly more effective than selenium.

[Peak expiratory flow rate (PEF) and serum eosinophil cationic protein (ECP) changes in nocturnal asthmatics]

We have investigated the serum ECP and peak expiratory flow rate in 20 patients with nocturnal asthma. Changes of PEF were measured in every 2 hours around the whole day, and the blood samples were obtained at 4:00 and 16:00 to measure the serum ECP level and the peripheral Eo numbers. In addition, 10 asthmatics as well as normal subjects received methacholine challenge at 4:00 and 16:00. It was found that the PEF reached the lowest point at 4:00 and obviously less than that at 16:00 (187.50 +/- 120.31 L/min vs 313.00 +/- 108.14 L/min, P < 0.05), that the airway reactivity at 4:00 was significantly higher than at 16:00 (P < 0.05) and the difference of MCH-PC20 between the two time points was 0.34 +/- 0.31 mg/ml, that the serum ECP level at 4:00 was obviously higher than that at 16:00 (11.14 +/- 7.40 micrograms/ml vs 5.49 +/- 4.12 micrograms/ml, P < 0.05). The change rate of PEF markedly related to the change of serum ECP between the two time points (r = 0.61, P < 0.05). The findings suggested that the activation of Eo and its release of ECP might be effect of the circadian-rhythmic change of pulmonary functions in nocturnal asthma.

[Full thickness lamellar keratoplasty with viscodelamination of cornea for treatment of bullous keratopathy]

Intrastromal injection of viscoelastic (2% methylcellulose or healon) will facilitate the separation of deep stroma during dissection of recipient stroma. Full thickness lamellar keratoplasty was performed on a smooth graft bed which approached Descemet's membrane. 21 cases with bullous keratopathy were treated and followed up for six months, post-operatively. The symptoms were controlled in all cases and 13 cases were relieved from blindness with corrected visual acuities over 0.05. The safety, efficacy and reoperability of full thickness lamellar keratoplasty with viscodelamination of cornea for treatment of bullous keratopathy make it a promising technique.

Ultrabithorax protein is necessary but not sufficient for full activation of decapentaplegic expression in the visceral mesoderm

To elucidate the mechanisms by which homeotic selector (HOM) genes specify the unique features of Drosophila segments, we have analyzed the regulation of decapentaplegic (dpp), a transforming growth factor (TGF)-beta superfamily member, and have found that the Ultrabithorax (Ubx) HOM protein directly activates dpp expression in parasegment 7 (PS7) of the embryonic visceral mesoderm. Other factors are also required, including one that appears to act through homeodomain protein binding sites and may be encoded by extradenticle (exd). The exd protein binds in a highly co-operative manner to regulatory sequences mediating PS7-specific dpp expression, consistent with a genetic requirement for exd function in normal visceral mesoderm expression of dpp. A second mechanism contributing to PS7 expression of dpp appears not to require Ubx protein directly, and involves a general visceral mesoderm enhancer coupled to a spatially specific repression element. Thus, even in an apparently simple case where visceral mesoderm expression of the dpp target gene mirrors that of the Ubx HOM protein, full activation by Ubx protein requires at least one additional factor. In addition, a distinct regulatory mode not directly involving Ubx protein also appears to contribute to PS7-specific expression.

Alveolar-to-vascular leakage of surfactant protein A in ventilated immature newborn rabbits

We measured alveolar-to-vascular leakage of surfactant protein A (SP-A) in immature newborn rabbits delivered at a gestational age of 27 days. Experimental animals received, via a tracheal cannula, 2 ml/kg of a mixture of modified porcine surfactant (Curosurf, 80 mg/ml) and human recombinant SP-A (4 mg/ml). Littermate controls received the same volume of human SP-A in saline (4 mg/ml). After 30 min of artificial ventilation with a frequency of 40/min and an inspiration time of either 0.75 or 0.45 s, blood was sampled from the right ventricle and the lungs were lavaged. The content of human SP-A in serum and lung lavage fluid was determined with ELISA kits, and the alveolar-to-vascular leak expressed as the quotient of total SP-A in serum and lavage fluid. The leak in control animals amounted to about 2% of SP-A in lung wash and was several times higher in these animals than in those receiving surfactant. The leak was of the same order irrespective of whether the animals were ventilated with long or short inspiration time. We speculate that serum levels of SP-A may reflect the degree of lung injury in various forms of respiratory failure.

Experimental neonatal group B streptococcal pneumonia: effect of a modified porcine surfactant on bacterial proliferation in ventilated near-term rabbits

We studied bacterial proliferation in relation to surfactant treatment in a model of neonatal group B streptococcal (GBS) pneumonia. Surfactant (Curosurf) was isolated from pig lungs with a method preserving only polar lipids and hydrophobic proteins. Near-term rabbit fetuses were ventilated in a body plethysmograph system. At 15 min, a suspension of GBS strain 090 Ia LD (5 mL/kg, concentration approximately 10(9)/mL) was instilled intratracheally. At 30 min, surfactant (n = 12) or sterile saline (n = 13) was administered via the airways (2.5 mL/kg). A control group (n = 12) received the same volumes of saline. After 5 h the animals were killed, and samples for blood cultures and blood gases were taken from the heart. The left lung was aseptically removed, weighed, homogenized, serially diluted, and cultured on blood agar plates. The results were expressed as mean log10 colony forming units/g lung +/- SD. Compared with animals (n = 12) killed immediately after GBS instillation (8.13 +/- 0.54), there was a significant increase in bacterial numbers in both groups ventilated for 5 h, but values for surfactant-treated animals (8.96 +/- 0.38) were lower than those for animals receiving saline (9.46 +/- 0.50; p < 0.05). After 5 h, 96% of GBS-infected animals had positive blood cultures. Light microscopic examination of the right lung of GBS-infected animals revealed inflammatory changes that tended to be less prominent in surfactant-treated rabbits. We conclude that intratracheal inoculation of near-term rabbits with GBS resulted in a significant bacterial proliferation during 5 h of ventilation and that bacterial growth was mitigated by treatment with surfactant.

Comparison of surface properties and physiological effects of a synthetic and a natural surfactant in preterm rabbits

AIMS

To compare the physical and physiological properties of a synthetic surfactant (Exosurf, Wellcome Foundation) and a natural surfactant (Curosurf, Chiesi Farmaceutici).

METHODS

Surface properties of the surfactant suspensions (10 mg phospholipid/ml) were evaluated using the pulsating bubble surfactometer. Lung-thorax compliance was determined in 47 immature newborn rabbits with a gestational age of 27 days, treated with recommended clinical doses of either surfactant (Exosurf 67.5 mg/kg; Curosurf 200 mg/kg). The lungs were examined histologically.

RESULTS

The mean (SD) contractile forces of the surface at maximum and minimum bubble size were significantly lower for Curosurf than for Exosurf: 31 (2) and 0 (0) mN/m v 53 (5) and 29 (4) mN/m, respectively. Mean (SD) lung-thorax compliance after one hour of ventilation was significantly higher in rabbits treated with Curosurf compared with animals receiving Exosurf or those serving as controls: 0.60 (0.15) ml/cm H2O.kg v 0.44 (0.03) and 0.34 (0.18) ml/cm H2O.kg, respectively. Both surfactants increased alveolar volume density compared with results for control animals, but only Curosurf significantly reduced the incidence of moderate or severe bronchiolar epithelial disruption.

CONCLUSIONS

The natural surfactant, Curosurf, reduced the contractile force at an air-liquid interface to a greater extent than the synthetic surfactant, Exosurf, and led to a greater improvement in compliance and less airway epithelial damage when given in clinical treatment doses to immature rabbits.

Exogenous surfactant improves lung compliance and oxygenation in adult rats with meconium aspiration

We studied the effects of exogenous surfactant on lung function and morphology in an adult rat model of severe meconium aspiration syndrome. Animals ventilated with 100% oxygen received 4-6 ml of human meconium (25 mg/ml) intratracheally. After 30 min, lung-thorax compliance had decreased by > 30% and arterial PO2 was < 10 kPa. Animals were then treated with no material (MECO group), 0.9% NaCl (MECO-saline group), natural porcine surfactant (NPS group) at a dose of 100 mg/kg, or modified porcine surfactant at a dose of either 100 (MPS100 group) or 200 mg/kg (MPS200 group) and were ventilated for another 180 min. Immediate and sustained improvement of arterial PO2 and compliance was observed in the MPS200 group, whereas the MPS100 and NPS groups showed less pronounced effects. There was a significant improvement of quasi-static lung volumes at maximum insufflation pressure and during deflation in the MPS200, MPS100, and NPS groups. Recordings with Wilhelmy balance showed that minimum surface tension of bronchoalveolar lavage fluid from animals receiving either type or dose of surfactant was significantly lower than in the MECO and MECO-saline groups. Meconium aspiration induced diffuse and prominent atelectasis, intra-alveolar edema, and hyaline membranes. These morphological abnormalities were reversed by exogenous surfactant, especially by the high-dose regimen.

[Animal experiments on meridian-reaching actions of traditional Chinese medicinal herbs]

With the level variations of cAMP and cGMP in cat tissues as the criteria, the meridian actions reaching of Fructus Schisandrae, Radix Stephaniae Tetrandrae and Herba Houttuyniae were studied tentatively in animal experiments. The result obtained in this way approximates to the understanding of the meridian reaching actions of Chinese medicinal herbs as approved by traditional Chinese medicine.

[Heel reconstruction by the composite island flap of the lower leg]

From 1987, 6 to 1992, 6 cases of heel defect were repaired successfully by reverse transfer of the composite island flap from the lateral lower leg. The flap, pedicled with peroneal vessels, consisted of skin, subcutaneous tissue, fibula and adjacent muscles. The contour and function were satisfactory.

[A 5-year retrospective investigation of occupation-related burns in Zhenjiang area]

During the 5 years from June 1986 to June 1991, 221 patients were admitted to our department of burn surgery because of occupation-related burns. The average age was 31.2 years, and 83.4 per cent was male. Most of the patients (79.6 per cent) were referred to our hospital within 24 h of their injury. The most common etiology was flame (33.0 per cent). The mean body surface area of all 221 cases was 17.1 per cent, with a mean full-thickness component of 8.1 per cent.

COMPLICATIONS

inhalation injury 18 cases (8.1 per cent); sepsis 5 cases (2.3 per cent) confirmed by positive blood cultures at an average time of 10.2 days postburn, and the commonest organism was pseudomonas aeruginosa; pneumonia 5 cases (2.3 per cent). The mortality of these 221 cases was 1.8 per cent. The average time of stay in our hospital was 34.3 days. The total expenditure was about 740,000 Yuan. First aid on the spot and early correct treatment are stressed. It is essential to put prevention first, and the measures to lower the incidence of occupation-related burns were discussed to serve as a reference for labor protection department and occupation-related burns institute.

[A clinic report of 54 cases of reconstruction for the anterior segment of eye]

54 cases (54 eyes) of severe injury in the anterior segment of eye with little light perception were treated by reconstruction for the anterior segment of eye. The results showed that the eyeballs in 48 cases (88.9%) were survived successfully, and 28 cases (51.9%) of the grafts were clear. The procedures included keratoplasty, iridectomy, lensectomy, anterior vitrectomy, and reconstruction of the anterior chamber to restore the cosmetic shape of the eyeball. The indications, complications of the operation, and the surgical technique are discussed.

[Comparative studies of 111In-labeled monoclonal antibody using spacer-containing and non-spacer bifunctional chelates: (I). Conjugation, labeling, immunoreactivity and in vitro stability]

Bifunctional chelates containing chemical spacer, succinimido-EGS-DTPA (EGS-DTPA, diester spacer) and 1-[4-(10-maleimidopropyl)amidobenzyl]ethylenediamine-N,N,N', N'- tetraacetic acid (C10-Bz-EDTA, hydrocarbon spacer) were synthesized and compared in vitro with non-spacer chelates, cyclic DTPA dianhydride (cDTPAA) and isothiocyanatobenzyl-EDTA (SCN-Bz-EDTA). The optimum condition for conjugation with chelates, labeling efficiency, immunoreactivity and stability in the serum were investigated with respect to four chelates. The labeling efficiency for EGS-DTPA-A7 and DTPA-A7 was 90% and over 95%, respectively, when reacted by the chelate to antibody ratios of 10:1 for EGS-DTPA and 2:1 for cDTPAA. The labeling efficiency for SCN-Bz-EDTA and C10-Bz-EDTA was 70% and 80%, respectively, when both of the chelates were conjugated with the antibody in a 1:1 ratio. EGS-DTPA-A7 and DTPA-A7 were unstable when incubated in the human serum at 37 degrees C and showed the transchelation to the transferrin fraction of the 111In activity. Furthermore, the radioactivity from 111In-EGS-DTPA-A7 was also found to be associated with the In-DTPA fraction, indicating that the diester spacer was cleaved in the serum. SCN-Bz-EDTA-A7 and C10-Bz-EDTA-A7 were very stable: there was no evidence of transchelation or any activity was dissociated from the conjugated antibody when incubated in the human serum for 168 hrs. Using C10-Bz-EDTA, immunoconjugate with sufficient specific activity was obtained and high immunoreactivity was maintained. It was considerable that the C10-Bz-EDTA immunoconjugate would produce preferable biodistribution than EGS-DTPA immunoconjugate do.

[Comparative studies of 111In-labeled monoclonal antibody using spacer-containing and non-spacer bifunctional chelates: (II). Biodistribution, metabolism and excretion in vivo]

Indium-111-labeled A7 monoclonal antibodies using two spacer-containing chelates, succinimido-EGS-DTPA (EGS-DTPA: diester spacer) and maleimido-C10-Bz-EDTA (C10-Bz-EDTA: hydrocarbon spacer) were investigated in human LS180 colon tumor bearing nude mice and were compared with two non-spacer chelates, cyclic DTPA dianhydride (cDTPAA) and isothiocyanatobenzyl-EDTA (SCN-Bz-EDTA). Compared with immunoconjugates using non-spacer chelates, immunoconjugates using spacer-containing chelates, especially C10-Bz-EDTA-A7 showed lower 111In activity in normal organs. The radioactivity in the liver for C10-Bz-EDTA-A7 decreased continuously till 96 hrs postinjection, however, this liver radioactivity for EGS-DTPA-A7 showed little change after 24 hrs. Moreover, in liver subcellular distribution study, EGS-DTPA-A7 showed a higher activity retention in mitochondrial fraction which contained lysosome, a place for metabolizing and storing of 111In labeled antibody, than that of C10-Bz-EDTA-A7. The C10-Bz-EDTA-A7 conjugate demonstrated more preferable tumor-to-non tumor contrast on the scintigrams than that found with other three immunoconjugates. Up to 96 hrs postinjection, tumor bearing nude mice injecting with immunoconjugates using spacer-containing chelates excreted twice radioactivity from whole body than that excreted by using non-spacer chelates. Interestingly, different from other three chelates, C10-Bz-EDTA-A7 were mainly excreted via feces. We conclude that the decrease of radioactivity in normal tissues in the case of EGS-DTPA-A7 was duo to the rapid decrease of activity in the blood, while in the case of C10-Bz-EDTA-A7 it was due to the quickly excreted small metabolite through faces. 111In labeled C10-Bz-EDTA conjugate is superior, at least when conjugated with A7, to other three chelate conjugates used in this study.

In vitro expression of calcitonin gene-related peptide in human endothelial cells transfected with plasmid and retroviral vectors

Introduction of cDNA encoding human alpha-calcitonin gene-related peptide (CGRP), a potent vasodilator, into cultured human umbilical vein endothelial cells (HUVEC) was undertaken by using plasmids and retroviral vectors. In order to improve expression, modification of context coding sequence for the initiation of CGRP translation and deletion of nontranslated regions of CGRP cDNA in the transfection vectors were tested. Stable transfer of neo in the HUVEC was achieved with both plasmid and retroviral vectors. Integration rates obtained by using retrovirus (approximately 1%), where higher than those achieved with plasmid-mediated transfection (< 1/1000). CGRP expressed in the transfected HUVEC was secreted into culture medium when a leading sequence was included in the expression vectors. CGRP was detected by enzyme-linked immunosorbent assay (ELISA) in the supernatants of both transiently transfected and stably transfected/infected HUVEC. Higher levels of expression were achieved by using plasmid (giving a maximum CGRP concentration of 6.5 +/- 0.5 pM in the supernatant) than retroviruses. Lipofectin-mediated transfer of CGRP cDNA also resulted in transient expression of CGRP in the HUVEC.

Biochemical analysis of proteins recognized by anti-HRP antibodies in Drosophila melanogaster: identification and characterization of neuron specific and male specific glycoproteins

Antibodies recognizing horse radish peroxidase (HRP) stain neurons in Drosophila and other insects. We have used Western blots to analyze and characterize some of the anti-HRP reactive components from Drosophila melanogaster. Anti-HRP reactive components can be reproducibly detected during all developmental stages, although the pattern changes at different developmental times. In adults, there are at least 10 reproducibly stained components. Two of the bands, with molecular sizes of 42 and 80 kDa are likely to be the major contributors to neuronal anti-HRP staining in Drosophila. These components are enriched in adult fly heads. In contrast, many of the other anti-HRP reactive components in adults are enriched in abdomen and are present exclusively or at much higher levels in male flies. We have purified and characterized two of the male specific components with molecular sizes of 62 and 48 kDa. Partial N-terminal amino acid sequencing revealed that the 62 kDa protein is identical to a part of D. melanogaster carboxylesterase to EC 3.1.1.1) while he 48 kDa protein does not match any known sequences. Esterase-6 has previously been shown to be enriched in male accessory gland and consistent with this we show staining of this structure with anti-HRP antibodies.

Effect of endotoxin on lipid order and motion in erythrocyte membranes

Electron paramagnetic resonance employing a lipid-specific spin label has been used to investigate the molecular effects of endotoxin on the physical state of bilayer lipids in rat erythrocyte membranes. When added at a concentration as low as 40 micrograms/ml to whole blood (plasma plus leukocytes present), decreased membrane lipid motion was found in subsequently washed and spin-labeled intact erythrocytes (P < 0.02). However, if endotoxin were added to washed, plasma plus leukocyte-free intact erythrocytes, no change in the motion of the spin label was found, suggesting that plasma-soluble substances and/or leukocytes are required to produce the change in the physical state of lipids. The decreased lipid motion found in these studies is discussed with reference to the known decreased deformability of endotoxin-treated red cells and to the pathogenesis of sepsis.

Ethamsylate and lung permeability in ventilated immature newborn rabbits

The leakage of proteins in the immature neonatal lung can reduce the effect of exogenous surfactant. The effect of ethamsylate, a more specific prostaglandin inhibitor than indomethacin and aspirin-like drugs, on alveolar albumin leak was studied in a group of 27 immature newborn rabbits (gestational age 27 days). A pilot study was carried out using 4 animals and low-dose ethamsylate (10 mg/kg). A second group of animals (n = 12) received at birth, by intravenous injection, ethamsylate (50 mg/kg) and 10% human albumin (7 ml/kg). Animals not receiving ethamsylate (n = 11) served as control group. After 30 min of artificial ventilation with standard tidal volume (10 ml/kg) the lungs were lavaged and the amount of human albumin in lung lavage fluid was determined by immunodiffusion. No statistically significant differences were found in lung-thorax compliance and vascular to alveolar albumin leak between ethamsylate-treated animals and controls (p > 0.5). However, there was a statistically significant negative correlation between protein leak and lung compliance (r = -0.41; p < 0.04). These results suggest no direct influence of early ethamsylate administration on neonatal lung permeability in the immature neonate confirming that lung permeability is inversely related to compliance.

Changes of pulmonary glucocorticoid receptor and phospholipase A2 in sheep with acute lung injury after high dose endotoxin infusion

In a sheep model of acute lung injury induced by an Escherichia coli endotoxin (5 micrograms/kg) with chronic lung lymph fistula (n = 15), we measured the changes in glucocorticoid receptor (GCR) binding capacity in lung tissue by means of radioligand binding assay. The content of cortisol and the activity of phospholipase A2 (PLA2) were also measured. The results showed that the maximal binding capacity (Bmax) of GCR in lung cytoplasma decreased continuously 2 h (113 +/- 3 versus 66 +/- 2 fmol/mg protein, p < 0.01), 4 h (105 +/- 6 versus 52 +/- 3 fmol/mg protein, p < 0.01), and 6 h (105 +/- 5 versus 37 +/- 2 fmol/mg protein, p < 0.01) after endotoxin infusion. Its affinity decreased markedly (p < 0.05) at 6 h after the infusion. The contents of cortisol in plasma elevated at 0.5 h and remained at a high level until 4 h after the infusion. PLA2 activity rose from 97 +/- 25 to 188 +/- 12 U (p < 0.05), 99 +/- 13 to 285 +/- 25 U (p < 0.01), and 106 +/- 14 to 354 +/- 32 U (p < 0.01) at 2, 4, and 6 h after endotoxin infusion, respectively. There was a negative correlation between the Bmax of GCR and PLA2 activity (r = -0.87, p < 0.01). The findings indicate that there was a secondary GCR abnormality and a higher PLA2 activity during endotoxin-induced lung injury. The glucocorticoid hypofunction caused by reduced GCR binding capacity may accelerate the pathologic response of acute lung injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunochemical analysis of the gp120 surface glycoprotein of human immunodeficiency virus type 1: probing the structure of the C4 and V4 domains and the interaction of the C4 domain with the V3 loop

We have probed the structure of the C4 and V3 domains of human immunodeficiency virus type 1 gp120 by immunochemical techniques. Monoclonal antibodies (MAbs) recognizing an exposed gp120 sequence, (E/K)VGKAMYAPP, in C4 were differentially sensitive to denaturation of gp120, implying a conformational component to some of the epitopes. The MAbs recognizing conformation-sensitive C4 structures failed to bind to a gp120 mutant with an alteration in the sequence of the V3 loop, and their binding to gp120 was inhibited by both V3 and C4 MAbs. This implies an interaction between the V3 and C4 regions of gp120, which is supported by the observation that the binding of some MAbs to the V3 loop was often enhanced by amino acid changes in an around the C4 region.

Effects of acute hypoxia on intracranial dynamics in unanesthetized goats

The effects of acute hypoxia on intracranial dynamics were studied in six unanesthetized goats that were subjected to hypobaric hypoxia at a simulated 4,000-m high altitude for 2 h. Another six nonhypoxic goats served as control group for cerebral water content (CWC). In this study, we measured cerebral blood flow (CBF) by electromagnetic flowmeter, intracranial pressure (ICP) through an intraventricular catheter, and CWC by a wet-to-dry weight technique for a given volume of brain tissue. Intracranial compliance was calculated from a pressure-volume index derived from the change in intraventricular pressure after a subarachnoid injection of saline. During acute hypoxia CBF increased from 146.0 +/- 10.60 to 185.3 +/- 7.83 ml x min-1.100 g-1, ICP increased from 15.4 +/- 1.82 to 27.4 +/- 3.84 cmH2O, and CWC increased from 78.7 +/- 0.30 to 79.5 +/- 0.16%, but intracranial compliance decreased from 0.65 +/- 0.28 to 0.36 +/- 0.19 ml/cmH2O. The data suggest that acute hypoxia results in a significant disturbance of intracranial dynamics, which may be one of the important pathophysiological mechanisms of high-altitude cerebral edema and acute mountain sickness.

An analysis of antigenic polypeptides of dengue viruses and their specificity with western blotting

Dengue virus (DV) samples which harvested after having been either propagated in C6/36 cells or passaged by murine intracerebral inoculation were investigated by Western blotting. Two different denaturing methods with the same solution were selected before electrophoresis, one at 60 degrees C for 20 min; the other at 100 degrees C for 5 min. After the samples were heated at 60 degrees C for 20 min, 3 bands of sizes 46 ku, 70 ku and 98 ku were positively recognized by rabbit immunized sera. The peptide of 98 ku was DV group specific; While that of 46 ku could also react with the sera against both heterologous DV serotype and Japanese B encephalitis virus (JEV). After the samples were heated at 100 degrees C for 5 min, 3 peptides in size of 20 ku, 46 ku and 57 ku were recognized by the rabbit sera against both homologous and heterologous DV serotypes, while the peptide of 57 ku could also be recognized by anti-JEV serum. There was no significant difference in the results of Western blot between the DV antigens harvested from cellular culture and those from intra-cerebral inoculation.

Single dose versus two doses of betamethasone for lung maturation in preterm rabbits

Most previous studies of induced lung maturation have used fetal exposures to multiple doses of hormones, and such treatments are associated with fetal growth retardation in rodents and rabbits. This study was designed to evaluate whether single-dose maternal corticosteroid treatments could induce lung maturation without causing fetal growth retardation. Lung maturation was evaluated in 27-d gestational age rabbits by measurements of lung function after preterm delivery and ventilation. Lung function was assessed by measurements of ventilatory requirements, responses to exogenous surfactant, measurements of the recovery of intravascular albumin in the lungs, and surfactant pool sizes. As demonstrated previously, 0.1 mg/kg betamethasone (1 mg = 2.13 mumol betamethasone) given 48 and 24 h before delivery caused both growth retardation (birth weight 20% lower than controls, p < 0.01) and lung maturation (improved compliance, decreased radiolabeled albumin recoveries) despite lower alveolar saturated phosphatidylcholine pool sizes (p < 0.05 versus controls). A single dose of 0.2 mg/kg betamethasone given 48 h before delivery had an equivalent effect on birth weight as the divided doses of 0.1 mg/kg betamethasone, with the only lung maturational effect being a decrease in recovery of labeled albumin in alveolar washes (p < 0.01). A single dose of 0.1 mg/kg betamethasone given 48 h before delivery decreased birth weight by 9.4% (p < 0.01 versus control) but had no effect on any of the lung maturation indicators. Fetal lung maturation caused by maternal corticosteroid is associated with global fetal growth retardation, and a single low dose of corticosteroid can cause growth retardation without inducing lung maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Surfactant inhibition in experimental meconium aspiration

Human meconium components were separated into a water-methanol soluble phase containing mainly proteins and bilirubin and a chloroform soluble phase containing free fatty acids, triglycerides and cholesterol. Various amounts of original meconium, the water-methanol soluble fraction or the chloroform soluble fraction were added to standard suspensions of porcine surfactant (Curosurf). In a pulsating-bubble or Wilhelmy-balance system, meconium and its subfractions inhibited surfactant activity, but the chloroform soluble fraction had the highest specific inhibitory activity. Original meconium in saline (130 or 65 mg/ml) was instilled into the airways of ventilated near-term newborn rabbits (dose 6 ml/kg). Lung-thorax compliance was reduced by 38% in animals aspirating the higher dose and by 27% in the low-dose group. Histological sections showed intra-alveolar accumulation of fine meconium particles in experimental animals, but no plugging of larger airways. We conclude that respiratory failure from meconium aspiration may be mediated, in part, by inactivation of surfactant.

Normocalcemic blood or crystalloid cardioplegia provides better neonatal myocardial protection than does low-calcium cardioplegia

Although standard blood cardioplegia provides good myocardial protection for cardiac operations in adults, protection of the cyanotic, immature myocardium remains suboptimal. Calcium, which has been implicated in reperfusion injury and in the development of "stone heart" in mature myocardium, is routinely lowered in standard cardioplegic solutions. Immature, neonatal myocardium has lower intracellular calcium stores and is more reliant on extracellular calcium for contraction. To determine if normocalcemic cardioplegia would result in improved cardiac function in the neonatal heart, we conducted a series of experiments using an isolated, blood-perfused working heart model. Thirty-two neonatal piglet hearts (24 to 48 hours) were excised without intervening ischemia and were placed directly on a blood-perfused circuit. Baseline stroke work index was assessed. Hearts were then arrested with cold cardioplegic solution delivered at 45 mm Hg for 2 minutes: group I, low-calcium blood cardioplegic solution (Ca = 0.6 mmol/L); group II, normal-calcium blood cardioplegic solution (Ca = 1.1 mmol/L); group III, University of Wisconsin solution; and group IV, University of Wisconsin solution with added calcium (Ca = 1.0 mmol/L). Cardioplegic solution was administered every 20 minutes for 2 hours and topical hypothermia was used. Hearts were then reperfused with warm whole blood. Functional recovery, expressed as a percentage of control stroke work index, was determined minutes after reperfusion. Hearts preserved with normocalcemic cardioplegic solution (groups II and IV) had complete functional recovery at 60 minutes, whereas hearts preserved with low-calcium cardioplegic solution (groups I and III) achieved functional recoveries of only 80% and 65%, respectively, at a left atrial pressure of 9 mm Hg. Electron micrographs taken 1 hour after reperfusion showed minimal edema and only mild myofibrillar changes. They were identical in both the low-calcium and normocalcemic groups. Complete functional recovery is possible in immature myocardium when calcium is added to either blood or an intracellular crystalloid cardioplegic solution. The addition of calcium does not result in ultrastructural damage and does result in good functional recovery.

Quantitative autoradiography reveals higher densities of specific calcitonin-gene-related peptide receptors in small intramyocardial compared with large epicardial coronary arteries

1. Binding sites for calcitonin-gene-related peptide were localized and characterized in porcine coronary arteries using quantitative autoradiography, and the density of binding sites was compared between large epicardial and small intramyocardial coronary arteries. 2. A single class of binding sites for calcitonin-gene-related peptide with a dissociation constant of 2.1 +/- 0.2 nmol/l was detected in both the large and small coronary arteries. The density of specific binding sites was higher (maximum binding site density 231 +/- 14 fmol/mg of protein) in the small coronary arteries than in the large epicardial coronary arteries (maximum binding site density 108 +/- 5 fmol/mg of protein). beta-Human calcitonin-gene-related peptide showed higher affinity than alpha-human calcitonin-gene-related peptide for the binding sites. Most of the specific binding sites for both peptides in the large coronary artery were localized in the intima and media. 3. In coronary artery from patients with coronary heart disease, there were more binding sites for calcitonin-gene-related peptide in the smooth muscle layer of atheromatous segments (7.2 +/- 0.7 amol/mm2) than in that of normal segments (3.0 +/- 0.3 amol/mm2, P < 0.002). 4. The present findings lend further support to the theory of regional variation in the vasodilator response to calcitonin-gene-related peptide in porcine coronary arteries, which seems to be due to different densities of a single type of receptor for calcitonin-gene-related peptide.

Surfactant improves lung function and morphology in newborn rabbits with meconium aspiration

Nearly mature newborn rabbits (gestational age 29.5 days) were tracheotomized at birth and received, via the tracheal cannula, 6 ml/kg body weight of a filtered saline suspension of human meconium, 65 or 130 mg/ml. Animals were kept in body plethysmographs and ventilated for 60 min with standardized tidal volume (8-10 ml/kg). Aspiration of meconium caused, in both groups, a statistically significant reduction in lung-thorax compliance, elevated PCO2 in heart blood and reduced alveolar volume density (VV) in histological sections. Both groups responded to treatment with exogenous surfactant (Curosurf, 200 mg/kg) with a moderate, statistically significant improvement in lung-thorax compliance, PCO2 and alveolar VV. Our data indicate that respiratory failure after neonatal meconium aspiration may be influenced favorably by treatment with exogenous surfactant.

[Allergen-stimulated release of prostaglandin E, F2 alpha by alveolar macrophages from patients with allergic asthma]

Bronchoalveolar lavage (BAL) was performed in healthy subjects (n = 12) and patients with bronchial asthma (n = 11). Between the two groups there was no significant difference in the total number of cells and the percentage of alveolar macrophages (AM), lymphocytes (L), neutrophils (N) and eosinophils (E) in BAL fluids. When AM were cultured in vitro and stimulated with dermatophagoides farinae (DPF) antigen, the amount of PGE released by AM was significantly increased in the asthmatics. When the asthmatics, AM were sensitized with specific IgE positive serum and stimulated with DPF, they released more PGE and PGF2 alpha than those when specific IgE negative serum was used (P < 0.01). The PGE/PGF2 alpha ratio was significantly decreased. There was positive correlation between the decreased value of PGE/PGF2 alpha and patients, MCH-PC20. The increase in the amount of PGE and PGF2 alpha released and the decrease of PGE/PGF2 alpha ratio might play an important role in the pathogenesis of allergic asthma.

Different ventilation strategies alter surfactant responses in preterm rabbits

The effect of ventilation strategy on in vivo function of different surfactants was evaluated in preterm rabbits delivered at 27 days gestational age and ventilated with either 0 cmH2O positive end-expiratory pressure (PEEP) at tidal volumes of 10-11 ml/kg or 3 cmH2O PEEP at tidal volumes of 7-8 ml/kg after treatment with one of four different surfactants: sheep surfactant, the lipids of sheep surfactant stripped of protein (LH-20 lipid), Exosurf, and Survanta. The use of 3 cmH2O PEEP decreased pneumothoraces in all groups except for the sheep surfactant group where pneumothoraces increased (P < 0.01). Ventilatory pressures (peak pressures - PEEP) decreased more with the 3 cmH2O PEEP, low-tidal-volume ventilation strategy for Exosurf-, Survanta-, and sheep surfactant-treated rabbits (P < 0.05), whereas ventilation efficiency indexes (VEI) improved only for Survanta- and sheep surfactant-treated rabbits with 3 cmH2O PEEP (P < 0.01). Pressure-volume curves for sheep surfactant-treated rabbits were better than for all other treated groups (P < 0.01), although Exosurf and Survanta increased lung volumes above those in control rabbits (P < 0.05). The recovery of intravascular radiolabeled albumin in the lungs and alveolar washes was used as an indicator of pulmonary edema. Only Survanta and sheep surfactant decreased protein leaks in the absence of PEEP, whereas all treatments decreased labeled albumin recoveries when 3 cmH2O PEEP was used (P < 0.05). These experiments demonstrate that ventilation style will alter a number of measurements of surfactant function, and the effects differ for different surfactants.

Effect of amiloride and surfactant on lung liquid clearance in newborn rabbits

Immature and nearly mature fetal rabbits (gestational age 27.5 and 29.5 days, respectively) were obtained by hysterotomy and tracheotomized at birth. Immature rabbits received, via the tracheal cannula, 2.5 ml/kg of either normal saline, porcine surfactant (60 mg/ml), 1 mM amiloride in normal saline, or a mixture of surfactant and amiloride; nearly mature rabbits received either normal saline, or 1 mM amiloride in saline. The neonates were ventilated with a tidal volume of approximately 10 ml/kg for 0-60 min (immature animals) or 0-120 min (nearly mature animals). The lungs were then excised for determination of wet lung weight/body weight ratio (LW/BW). The right lung was further processed for quantification of extravascular lung water (EVLW) per unit dry lung weight, and the left lung fixed for measuring the size of perivascular 'cuffs' (adventitial tissue including lymphatics) in histological sections, using vascular lumen as reference volume. Immature animals receiving surfactant had improved compliance and smaller perivascular cuffs in comparison with the other groups. In immature animals amiloride had no effect on compliance, LW/BW, and EVLW, but reduced perivascular cuff size at 15 min. Nearly mature animals receiving amiloride had higher values for LW/BW and EVLW at 120 min, and lower perivascular cuff size at 15, 60, and 120 min, in comparison with saline-treated litter-mates. We conclude that surfactant improves lung-thorax compliance and reduces perivascular fluid accumulation in immature newborn animals without influencing total lung water content, and that amiloride retards fetal lung liquid resorption in nearly mature newborn animals without affecting lung-thorax compliance during artificial ventilation.

Antenatal ambroxol effects on surfactant pool size and postnatal lung function in preterm ventilated rabbits

Following maternal treatments with 50 mg/kg/day ambroxol for 2 or 3 days before delivery at 28 days gestation, preterm rabbits were ventilated to evaluate lung function. Subsequently, surfactant saturated phosphatidylcholine (SatPC) pool sizes were measured. One half of the ambroxol treated and control rabbits were given surfactant at delivery. Although surfactant improved lung function comparably for control and ambroxol treated rabbits, ambroxol treatments did not change ventilatory pressure requirements, compliances, or the recovery of intravascular labeled albumin in the lungs. Ambroxol treatments tended to increase lung volumes as evaluated by pressure-volume curves. The ambroxol treatments significantly increased lung tissue SatPC by 22%, but there were no changes in alveolar SatPC pool values. These results do not indicate a large effect of ambroxol on lung function in preterm rabbits.

[An experimental research on the acute lung injury induced by endotoxin]

Using a goat endotoxin model with chronic lung lymph fistula, we continuously measured lung lymph flow (QL), lymph to plasma protein ratio (L/P), pulmonary arterial pressure (Ppa) and the level of thromboxane B2 in plasma and lymph. We also observed the changes of ultrastructure in leukocyte and pulmonary parenchyma. It showed that the alteration can be divided into two intervals: phase I is characterized by the abrupt onset of pulmonary hypertension and in phase II, the capillary permeability increased predominantly. It was suggested that this model is a good research tool for studying adult respiratory distress syndrome (ARDS).

Studies on monoclonal anti-idiotypic and anti-isotypic antibodies against leukemia and myeloma: III. Analysis of monoclonal antibodies recognizing the antigenic epitopes by use of ELISA additivity test and microcomputer grouping programme

ELISA double antibodies additivity test was employed to identify the epitopes which can be recognized by monoclonal antibodies (McAbs) against IgM of a patient with B chronic lymphocytic leukemia (B-CLL). The computer grouping programme analysis showed that 4 anti-isotype McAbs could be divided into two groups and 10 anti-idiotype McAbs could be divided into four groups. The result was consistent with that of the indirect ELISA, ELISA sandwich as well as ELISA inhibition test. The above findings suggested that there are at least 6 distinct IgM epitopes which can specifically react with 14 McAbs. Our study indicated that the combination of the ELISA additivity test and the computer grouping programme analysis provides a helpful tool for researchers into the relationship between the structure and function of antigens.

[Airway challenge test with propranolol]

We investigated airway response to propranolol in 48 asthmatics, 17 subjects with chronic bronchitis and 19 normal subjects. The positive rate for propranolol challenge was 93.8% in asthma group, 5.9% in chronic bronchitis group while none in normal group had positive response. The challenge was highly reproducible, and it had few side-effects. This indicated that the challenge was specific and sensitive in diagnosis of asthma, it was a safe, reliable method of measuring non-specific airway responsiveness. Furthermore we also demonstrated that PC20 for propranolol did not relate to PC20 for methacholine, and that the calibre of airway did not significantly influence the airway response to propranolol.

Influence of cirrus clouds on the VISSR atmospheric sounder-derived sea surface temperature determinations

Using a more realistic cirrus cloud model, the characteristics of transmittance, emittance, and optical thickness and their relationships to cirrus in a diverse set of cases are studied by solving the equation of transfer of IR radiation. The doubling method is employed in the multiple scattering calculation. The satellite-observed brightness temperatures for different cases are computed, and stepwise regression analyses are performed to yield retrieval equations for sea surface temperature (SST). It is shown that the radiative properties of cirrus depend strongly on particle concentration, thus on the optical thickness of clouds. For clear atmospheres, channel 8 (11.2 microm) is more transparent than other channels. For cirrus clouds only, when the optical thickness of cirrus tau(c) is <0.10, channel 8 is still more transparent, while, with tau(c) increasing from 0.2 to between 4 and 8, channel 12 (4 microm) becomes the most transparent. When tau(c) >/= 8, the transparency of channel 12 decreases and those of other channels increase. For a very large r, the transparency of VAS channels will become almost equal. In addition, the IR absorption emittance of cirrus and the brightness temperatures also have sensitivities to different cloud optical thicknesses. The general retrieval equation for the determinations of SST, which is suitable for the clear air model as well as for the cirrus cloud atmospheres (with our definition of cirrus), is obtained through a combination of channels 12, 8, 6 (4.5 microm), and 5 (13.3 microm).The retrieval error is <1.0 K. The error analyses indicate that the clear air retrieval equations should not be used for SST determination in cirrus conditions.

[Ultrasonically nebulized hypertonic saline as a provocation agent in asthmatics]

We investigated nonspecific reactivity to inhaled aerosol of hypertonic saline. Hyperosmotic challenge carried out with NaCl solution of 0.9-fold increasing concentration from 2.7 to 7.2%. Each aerosol inhalation at different concentration was carried out for 5 min. An ultrasonic nebulizer was used to generate aerosol of NaCl solution that was delivered by tubing to a two-way valve. FEV1 was measured 1.0, 1.3 and 2 min after each concentration and did further at 5 min intervals until the value reached a plateau or began to rise. The challenge was terminated when the percentage fall in FEV1 was greater than 20%. The response to HS was expressed as PC20. In the 26 subjects with stable asthma 23 were responsive to HS. The PC20-HS was from 1.65 to 6.06%. The peak bronchoconstrictor effect of HS inhalation occurred 3 min after inhalation and its mean duration was 45 min. We also compared bronchial response to HS with that to methacholine (MCH). There was a significant correlation between PC20-HS and PC20-MCH (r = 0.538, P less than 0.01). The method used for HS challenge is simple, rapid, inexpensive and provide a new means for determination of bronchial hyperreactivity.