[Localization of fibronectin in atherosclerotic lesions by immunohistochemistry and immunoelectron microscopy]

This paper reports the results of a study on the distribution of fibronectin (FN), its form, character and source in atherosclerotic lesions, using immunohistochemistry (PAP method) and immunoelectron microscopic technique. The results showed that large amounts of FN were localized in fatty streaks, gelatinous lesions and early atherosclerotic plaques. The intima smooth muscle cells in atherosclerotic lesions synthesized more FN, and it is likely that FN represents a new marker of smooth muscle cell modulated from "contractile" to "synthetic" state. With the maturation of atherosclerotic plaque, FN did not fill the whole plaque but was concentrated only in the fibrous cap surface and basocentral part of the atheroma. We also proved that procollagen III peptide (PIIIP) distribution in atherosclerotic plaque was similar to that of FN.

Development of collagen fibers and vasculature of the fetal TMJ

Using 12 human fetuses, histological development and changes in connective fiber structure and fine vascular patterns have been investigated in various fetal gestational stages by light and scanning electron microscopy. The main arterial supply of the articular disc was from the bilaminar region and pterygoideus lateralis muscle. The vascular network on the disc surface was related with fluid secretion. When the bilaminar region was compressed, it caused ischemia and fibrosis as the main pathological changes in TMJ derangement. A decrease in fluid from blood vessels might occur in TMJ degeneration. Collagen fibers in the disc passed mainly anteroposteriorly. In the anterior and posterior bands, muscular tendon fibers came from the pterygoideus lateralis muscle and superior stratum of the bilaminar region. In the posterior band three-dimensional structures of collagen fibers suitable for load bearing were observed. The compass network and process on the disc showed the normal structure that is formed gradually and has functions including dispersion, pressure bearing, friction-proofing and storage of the synovial fluid. Attachments of the disc were suitable for disc function. Large elastic fibers in the posterolateral part of the superior stratum of the bilaminar region may be antagonistic to the upper head of the pterygoideus lateralis muscle fibers passing medioanteriorly, indicating that this antagonism is available for disc function.

Role of sodium and water excretion in the antihypertensive effect of vasopressin in the spontaneously hypertensive rat

Mean arterial pressure (mmHg (1 mmHg = 133.322 Pa)), sodium excretion rate (mumol.kg-1.min-1), and urine flow (microL.kg-1.min-1) were measured in conscious unrestrained spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) before, during, and after a 3-h intravenous infusion of arginine vasopressin (20 ng.kg-1.min-1), an equipressor dose of phenylephrine, or an infusion of the vehicle. Cessation of the phenylephrine infusion was associated with a return of arterial pressure to preinfusion control values in both SHR and WKY. Cessation of the vasopressin infusion was also associated with a return of arterial pressure to preinfusion values in WKY. In contrast, in the SHR, arterial pressure fell from a preinfusion control level of 164 +/- 6.2 to 137 +/- 4 mmHg within 1 h of stopping the vasopressin infusion. Five hours after stopping the infusion, pressure was 134 +/- 3 mmHg (29 +/- 5 mmHg below preinfusion levels). Similar to the WKY, cessation of a vasopressin infusion was associated with a return of arterial pressure to preinfusion values in Sprague-Dawley rats. Thus, the failure to observe a hypotensive response in normotensive rats was not a peculiarity of the WKY strain. Sodium excretion rates increased during the infusions of vasopressin to a greater extent in SHR than in WKY. However, the natriuresis induced by phenylephrine was not significantly different from that generated by vasopressin in SHR, and in WKY, the natriuresis was greater for phenylephrine than for vasopressin. Urine output increased to a greater extent during the infusions of phenylephrine in both SHR and WKY than during vasopressin infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adoptive transfer of V beta 2-deleting activity with host cells from mice implanted with C4 preneoplastic hyperplastic alveolar nodules

Selective deletion of mature peripheral V beta 2+ T-cells was observed in BALB/c mice implanted with the syngeneic C4 preneoplastic hyperplastic alveolar nodule (HAN) but not in mice with sham surgery (W. Z. Wei, R. Ficsor-Jacobs, S. J. Tsai, and R. Pauley, Cancer Res., 51:3331-3333, 1991). We now report the participation of host cells in that process. Peripheral V beta 2+ T-cells were reduced by 50% or more 4 weeks after an i.v. injection of 10 x 10(6) spleen cells from C4 HAN-bearing mice. Both T- and B-cell-enriched splenocytes mediated V beta 2 deletion. Secondary adoptive transfer of splenocytes from the recipients of the primary adoptive transfer also resulted in V beta 2+ T-cell deletion. The splenocytes lose V beta 2-deleting activity after 500 rad irradiation. V beta 2 deletion induced by either C4 HAN or splenocytes was more profound in CD4+ than in CD8+ T-cells. Loss of V beta 2+CD4+ T-cells was observed 5 days after the adoptive transfer of splenocytes, whereas V beta 2+ CD8+ cells were not reduced until day 9 or later. The differential rate of V beta 2+ CD4+ and CD8+ T-cell reduction continued for at least 7 weeks after the adoptive transfer. The pattern of V beta 2 deletion and the sequence of T-cell loss is similar in the recipients of C4 HAN or of adoptively transferred splenocytes. Southern blot analysis demonstrates non-germ line Mtv or MMTV proviral DNA in C4 HAN. Splenocytes of C4 HAN-bearing mice express a higher level of 1.7-kilobase long terminal repeat transcript than normal BALB/c splenocytes, suggesting a role for a unique Mtv/MMTV provirus in V beta 2 deletion.

Quantitative determination of FtsA at different growth rates in Escherichia coli using monoclonal antibodies

FtsA is an essential cell division protein in Escherichia coli. Its synthesis in low amounts makes the investigation of its functions difficult. Partially purified FtsA protein was obtained by solubilizing cellular inclusion bodies after overexpression of the ftsA gene for the purpose of raising monoclonal antibodies. Mice were immunized with this FtsA protein fraction and their spleen cells were fused to Sp2/0-AG14 mouse myeloma cells. Hybrid cells were screened and two clones were positively identified as FtsA monoclonal antibody producers by enzyme-linked immunosorbent assay and Western blotting. A quantitative assay using these monoclonal antibodies indicated that the average number of FtsA molecules per cell to be between 50 and 200. However, the concentration of FtsA protein normalized to total cell protein was constant over a wide range of growth rates. This finding is in agreement with the hypothesized role of FtsA protein as a stoichiometric component of the septum.

Effect of brain lesions on [3H]ohmefentanyl binding site densities in the rat striatum and substantia nigra

We have recently demonstrated that [3H]ohmefentanyl, a non-peptidergic opioid ligand which was suggested to cross the blood brain barrier in contrast to other peptidergic opioid ligands, bound not only to mu opioid receptor sites but also to sigma sites. In order to examine whether [3H]ohmefentanyl can be used as a marker for mu sites, we investigated the effects of brain lesions on [3H]ohmefentanyl binding site densities, as compared with [3H][D-Ala2, MePhe4, Gly-ol5]enkephalin ([3H]DAGO), a selective mu ligand. These binding site densities were measured by quantitative autoradiography in the rat striatum and substantia nigra, two brain structures known to contain a high density of mu receptors, following lesions of the nigro-striatal dopaminergic pathway and striatal intrinsic neurons. Following unilateral nigral lesion with 6-hydroxydopamine, [3H]ohmefentanyl binding site densities were decreased in the patches (-35%) and matrix (-20%) of the ipsilateral striatum and in the lesioned substantia nigra pars compacta (-49%). Unilateral striatal lesion with quinolinic acid induced 72%, 61% and 50% decreases in [3H]ohmefentanyl binding in the patches and matrix of the lesioned striatum and in the ipsilateral substantia nigra pars reticulata, respectively. Similar results were obtained in the binding of [3H]DAGO. Indeed, a significant linear correlation was observed between [3H]ohmefentanyl and [3H]DAGO binding site densities. Therefore, mu opioid receptors may be mainly located on intrinsic neurons in the striatum, dopaminergic cell bodies in the substantia nigra pars compacta and nerve terminals of striatal efferents in the substantia nigra pars reticulata.(ABSTRACT TRUNCATED AT 250 WORDS)

Water binding capacity of mixtures of lens crystallins

The water binding capacity of mixtures of bovine lens crystallins were investigated by combined differential scanning calorimetry and thermogravimetric analysis techniques. Binary, ternary and quaternary mixtures of alpha, beta H, beta L, and lower molecular weight (LMW) crystallins were prepared in proportion of their natural abundance. The percentage of non-freezable water of the total water content was used as an index of the bound water in all these mixtures and it was obtained as a function of crystallin concentration. These experimental values were compared to theoretical values that were calculated from the water binding capacity of individual crystallins obtained previously [Bettelheim and Popdimitrova (1990) Exp. Eye Res. 50, 715-8]. The calculations were based on the assumption that the mixtures of crystallins have the same intermolecular interactions that exist in the individual crystallins. Thus, the difference between the experimental and theoretical curves is an indicator of the type of interactions that may exist among the different crystallins. In all mixtures the experimental bound water was higher than the theoretical, predicted value at physiological concentrations. The water binding capacity of the lyophilized thin lens sections, on the other hand, was lower than the theoretical, predicted value.

An efficient algorithm for MR image reconstruction and compression

In magnetic resonance imaging (MRI), the original data are sampled in the spatial frequency domain. The sampled data thus constitute a set of discrete Fourier transform (DFT) coefficients. The image is usually reconstructed by taking inverse DFT. The image data may then be efficiently compressed using the discrete cosine transform (DCT). We present here a method of using DCT to treat the sampled data, which combines two procedures, image reconstruction and data compression. This method may be particularly useful in medical picture archiving and communication systems (PACS) where both image reconstruction and compression are important issues.

Increased EGF binding and EGFR mRNA expression in rat aorta with chronic administration of pressor angiotensin II

This study examines the changes in the mRNA expression of epidermal growth factor (EGF), EGF receptor (EGFR), platelet derived growth factor (PDGF-B), and transforming growth factor beta (TGF-beta 1) before and after sustained pressor infusion of angiotensin II (Ang II) for 4 weeks. A threefold increase occurred in the levels of EGFR mRNA (17,240 +/- 827 vs 6403 +/- 1372 units, P less than 0.01) and TGF-beta 1 mRNA (1644 +/- 584 vs 475 +/- 30 units, P less than 0.01) only in the aorta and not in the heart and kidney tissues. This increase in both of the above mRNA transcripts highly correlated (r = 0.96 and 0.92, P less than 0.01) with the elevation of blood pressure. The specific binding of 125I-labeled EGF to aortic membranes also increased (11,429 +/- 728 vs 8630 +/- 420 cpm/mg protein, P less than 0.05) with a parallel increase in the protein tyrosine kinase activity of the membranes indicating that the enhanced EGFR mRNA expression resulted in increased activity of a functional receptor. No significant changes were observed in either EGF mRNA or PDGF-B mRNA levels. These findings suggest that EGFR and TGF-beta 1 participate in the long-term progressive pressor response to Ang II and thus potentially in the progression and the maintenance of chronic hypertension.

A simple, efficient PCR technique for characterizing bacteriophage plaques

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cDNA sequence of three cysteine-rich clusters in the iron-sulfur subunit of complex II (succinate-ubiquinone oxidoreductase) from Caenorhabditis elegans determined by automated DNA sequencer

Homology probing by using mixed primers for polymerase chain reaction (PCR) and a subsequent sequence analysis by automated DNA sequencer were applied to determine a partial cDNA sequence of the iron-sulfur subunit of complex II (succinate-ubiquinone oxidoreductase). Complex II is a membrane-bound flavoenzyme, which catalyzes the oxidation of succinate to fumarate in the tricarboxylic acid cycle, and it is a component of the mitochondrial and bacterial respiratory chains. In this study, the partial amino acid sequence of iron-sulfur subunits in Caenorhabditis elegans mitochondria was deduced from the DNA sequence obtained from cDNA-PCR. Mixed oligonucleotide primers corresponding to two conserved regions which appear to be the binding site for the prosthetic group were used. The product of PCR was cloned into plasmid vector pUC 119 and the sequence was determined from double strand plasmid DNA by the dideoxy method using of one-dye, four-lane type the automated DNA sequencer (DSQ-1, Shimadzu). The PCR product contained 483 nucleotides and its deduced amino acid sequence was highly homologous with that in human liver (68.9%) and that of Escherichia coli sdh B product (50.3%). As expected, striking sequence conservation was found around the three cysteine-rich clusters which have been thought to comprise the iron-sulfur centers of the enzyme.

Streptokinase-producing streptococci grown in human plasma acquire unregulated cell-associated plasmin activity

Group A streptococci grown in the presence of human plasma generated plasmin from plasminogen and captured the functional enzyme to a specific cell-surface receptor. Bacteria-bound plasmin was not regulated by alpha 2-antiplasmin present in the medium. The ability of the bacteria to acquire cell-associated plasmin activity was dependent on both the presence of plasminogen in the culture medium and the production of a bacterial plasminogen activator, streptokinase. The ability of group A streptococci to produce a plasminogen activator and capture resulting plasmin in an unregulatable form could provide the organism with a mechanism for invasion of normal tissue barriers.

Human monoclonal and polyclonal anti-human immunodeficiency virus-1 antibodies share a common clonotypic specificity

Human monoclonal and purified polyclonal anti-human immunodeficiency virus (HIV)-1 antibodies were tested for binding to a murine monoclonal anti-idiotypic antibody (1F7, IgM, kappa). Four human monoclonal anti-p24 and three human monoclonal anti-gp120 antibodies express the 1F7 clonotype, while one human monoclonal anti-gp41 antibody does not bind to 1F7. Affinity-purified anti-p24 and anti-gp120 antibodies from HIV-1-infected individuals also react with 1F7. Western blot analysis and enzyme-linked immunosorbent assay confirmed that 1F7 reacts with human antibodies of different HIV-1 antigen specificities. A survey of sera from 329 HIV-1-infected individuals showed binding to 1F7 in 239 sera (72.6%) while 1F7 was not reacting with 109 HIV-1-negative sera. These results show that 1F7 idiotype is an HIV-1 infection-associated clonotypic marker shared by anti-HIV-1 antibodies with different epitope specificites.

A colorimetric method for detection of specific ligand binding

The binding of IL-2 and IL-3 to the factor-dependent cell lines CTB6 and 32D, respectively, was determined using biotinylated ligand detected by the addition of a streptavidin/alkaline phosphatase conjugate and amplified with a phosphatase amplification system. Binding of both ligands was detectable after incubation with as little as 20 fmol of ligand and could be inhibited with a 10-fold molar excess of nonbiotinylated ligand. No binding was observed when biotinylated ligand was incubated with a receptor negative cell line (PC-12) and IL-2 was unable to compete with biotinylated IL-3 binding to 32D cells, further demonstrating specificity. These studies indicate that biotinylated ligands can be used as a nonradioactive method to detect specific, high-affinity cell surface receptors.

Microtubule pattern and the occurrence of pre-prophase bands in embryogenic cultures of black spruce (Pieca mariana Mill.) and non-embryogenic cultures of jack pine (Pinus banksiana Lamb.)

The organization of microtubules during interphase and prophase in embryogenic cultures of black spruce (Picea mariana) was investigated by indirect immunofluorescence. Somatic embryos of black spruce possessed an extensively branched and interconnecting network of fine interphase cortical microtubules. The development of pre-prophase bands (PPBs) in embryogenic black spruce cultures was compared with that in non-embryogenic cell cultures of jack pine (Pinus banksiana). PPBs in both species were initially arranged as a very broad array of microtubules, later (early to mid-prophase) becoming narrower and more intensely fluorescent. The occurrence of pre-prophase bands in relation to the number of phragmoplasts (i.e. PPB index) of black spruce somatic embryos was significantly higher (p<0.01) than that found for jack pine cells.

Expression of ethylene biosynthetic pathway transcripts in senescing carnation flowers

We have examined the expression of mRNAs for S-adenosylmethionine synthetase (EC 2.5.1.6), 1-aminocyclopropane-1-carboxylate (ACC) synthase (EC 4.4.1.14), and the ethylene-forming enzyme (EFE) in various floral organs of carnation (Dianthus caryophyllus) during the increase in ethylene biosynthesis associated with petal senescence. The abundance of ACC synthase and EFE mRNAs increased and S-adenosylmethionine synthetase transcripts decreased concomitantly with the ethylene climacteric in senescing petals. The increase in abundance of ACC synthase and EFE mRNAs in aging flowers was prevented by treatment with the ethylene action inhibitor 2,5-norbornadiene. Furthermore, an increase in ACC synthase and EFE transcripts was detected in petals from presenescent flowers within 3 to 6 hours of exposure to 2 microliters per liter of ethylene. The increase in ethylene production by senescing petals was associated with a concomitant increase in ethylene biosynthesis in styles, ovary, and receptacle tissues. In all tissues, this increase was associated with increased activities of ACC synthase and EFE. The increase in EFE activities by all floral organs examined was correlated with increased abundance of EFE transcripts. In contrast, the level of ACC synthase mRNA, as detected by the cDNA probe pCARACC3, did not always reflect enzyme activity. The combined tissues of the pistil exhibited high rates of ACC synthase activity but contained low levels of ACC synthase mRNAs homologous to pCARACC3. In addition, pollinated styles exhibited a rapid increase in ethylene production and ACC synthase activity but did not accumulate detectable levels of ACC synthase mRNA until several hours after the initiation of ethylene production. These results suggest that transcripts for ACC synthase leading to the early postpollination increase in ACC synthase activity and ethylene production are substantially different from the mRNA for the ethylene-responsive gene represented by pCARACC3.

Effects of a fibroblast-derived inhibitor on the growth of normal marrow and leukemic clonogenic cells

Blood cells develop in the bone marrow, controlled by a network of regulatory factors, some of which originate in the stroma. Previously, we found that most fibroblastoid (FB) cells growing in primary cultures of rat marrow bear surface antigens different from those found on FB of certain other tissues. As determined by two monoclonal antibodies ("ST3" and "ST4"), the "marrow type" is ST3+/ST4- and releases predominantly a colony-stimulating activity (CSA) into its culture media (CM), whereas the "peripheral type" (e.g. lung) is predominantly ST3-/ST4+ and produces inhibitory activity in excess of CSA. The studies described here show that this inhibitor also is active on rat leukemic myeloblasts (the BNML cell line), but not on eight other cell lines derived from rat tumors of various origins or on the human-derived leukemic cell lines tested. It was produced without exogenous stimulation, was labile to heat and acid, was not neutralized by antisera to transforming growth factor-beta, beta-interferon, or ferritin, and had an apparent mol wt in the range of 100-120 kD (peak of activity by gel filtration). From the results obtained at this time, we are not able to ascribe this fibroblast-derived activity to any known inhibitor molecule.

Preoperative risks predict neurological outcome of carotid endarterectomy related stroke

The aim of this study was to determine if preoperative risk factors are predictors of poor stroke outcome after carotid endarterectomy. In addition, the effect of other stroke risk factors on stroke severity was determined. A retrospective review of carotid endarterectomy results spanning 10 years, encompassing 561 patients, and reporting the combined results of all surgeons at our institution was performed. Patients were assigned to one of four groups. There were 227 patients with no preoperative risks (Group 1), 61 with angiographic risks (Group 2), 196 with medical risks with or without angiographic risks (Group 3), and 77 with neurological risks with or without medical/angiographic risks (Group 4). Other risks associated with stroke occurrence were recorded including: intraoperative risks (cross-clamp time, use of shunt, use of glucose solutions), surgical complications (carotid occlusion/thrombus or ligation), and medical complications (hypoxia, myocardial infarct). Stroke incidence was 5% with 2% (11 patients) and 3.4% (19 patients) having good and poor outcomes, respectively. Stroke incidence was highest in Groups 2 and 4 (10 and 14%, respectively), and Group 4 had the highest incidence of poor-outcome stroke (12%). Cross-clamp time, intraoperative shunt placement, and intraoperative glucose administration were similar among preoperative risk groups and were not primary determinants of stroke severity. The most common medical complication was myocardial infarction, which had the highest incidence in Groups 3 and 4 (6.1 and 5%, respectively). The highest incidence of surgical complications occurred in Groups 2 and 4, carotid thrombosis being the most common event (16 patients). Surgical complications were more commonly associated with stroke than were medical complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Consideration of dipole orientation angles yields accurate rate equations for energy transfer in the rapid diffusion limit

Dipole-dipole energy transfer between suitable donor and acceptor chromophores is an important luminescence quenching mechanism and has been shown to be useful for distance determination at the molecular level. In the rapid diffusion limit, where the excited-state lifetime of the donor is long enough to allow the donor and acceptor to diffuse many times their average separation before deexcitation, it is usually assumed that the relative dipolar orientation is completely averaged due to rotational Brownian motion. Under this simplifying assumption, analytical expressions have been derived earlier for the energy transfer rate between donor and acceptor characterized by different geometries. Most such expressions, however, are only approximate because complete angular averaging is permitted only in a geometry that possesses spherical symmetry surrounding each chromophore. In this paper analytical expressions that correctly account for incomplete angle averaging due to steric hindrance are presented for several geometries. Each of the equations reveals a dependence of the energy transfer rate on chromophore orientation. It is shown that correctly accounting for this effect can lead to improvements in estimates of the distance of closest approach from measured quenching rates based on energy transfer experiments.

Pilot production of high-titer interferon and virus with a microcarrier suspension culture system

We have successfully cultured four cell lines--L929, BHK-13, BHK-21 and CHO-K1 using an MC-1 type microcarrier made in our academy. With the microcarrier in a concentration of 5 mg/ml, the cell density was about 30 x 10(4) cells/ml; after 3 days in suspension culture, the cells could proliferate to 1 x 10(6) cells/ml. At this time, when L929 cells were primed with 25 IU/ml MuIFN for 14-24 h and then superinduced with NDV, cycloheximide (20 micrograms/ml) and actinomycin D (2 micrograms/ml), the titer of IFN reached approximately 10(5) IU/ml (10(5) IU/mg of protein, expressed in specific activity). When VSV was inoculated into the other three cell line cultures, the viral titer reached 6 Log TCID50/ml or much higher. The yield with the CHO-K1 cell line was the highest, reaching titers of 7-8 Log TCID50/ml. These titers were similar to those seen in stationary culture. With trypsin-citrate solution and a more rapid stirring speed, the cells could be satisfactorily released from the microcarriers and reattached on fresh ones. These experiments show that the microcarrier suspension culture system is suitable for producing large scale, high-titer, low-cost vaccines and IFNs, both natural and recombinant, using genetically-engineered CHO cell lines.

Atrial natriuretic factor and renin synthesized in cultured aortic smooth muscle cells of rats

This study was designed to determine whether or not atrial natriuretic factor (ANF) is present in the vascular walls and to observe the differences in ANF between control (WKY) and stroke-prone spontaneously hypertensive rats (SHRsp). It was found that ANF is indeed present in the vascular wall of the distal aorta. HPLC analysis of the extracts from cultured aortic smooth muscle cells (ASMC) and medium revealed that intracellular ANF was mainly in the form of ANF(1-126), at levels of 0.82 +/- 0.03 (SHRsp) and 1.04 +/- 0.10 ng/10(6) cells (WKY), while the major form in the medium was ANF(99-126), at levels of 0.40 +/- 0.06 and 0.60 +/- 0.06 ng/10(6) cells, respectively. Both forms were present in smaller amounts in SHRsp than in WKY rats. On the contrary, both renin activity and angiotensin I concentrations in SHRsp cells were significantly higher than those in the WKY controls. In addition, immunocytochemistry showed positive ANF staining in cultured ASMC of both strains. The results suggest that ANF can be synthesized and secreted by cultured ASMC from rats.

Interaction of immune sera with synthetic peptides corresponding to the structural protein region of hepatitis C virus

Comparison of the deduced amino acid sequence from the structural region of the Hutchinson strain of hepatitis C virus (HCV-H) with four other HCV isolates clearly divides the five isolates into two groups based on sequence homology. The first group includes HCV-H, HCV-1, and HC-J1, while the second includes HCV-J1 and HC-J4. Among the five isolates the first 190 residues (putative nucleocapsid) are highly conserved whereas residues 196-513 exhibit significant diversity and include a hypervariable region encompassing residues 386-404. A series of overlapping decapeptides were synthesized by solid-phase pin technology according to sequence from HCV-H (amino acids 1-513), HC-J4 (amino acids 181-513), and regions from the three other isolates which exhibited sequence variation. A modified ELISA was used to measure immunoreactivity of sera from clinical posttransfusion cases and experimentally infected chimpanzees. Comparison of pre- and postinfection samples revealed 16 clusters of immunoreactive peptides within the structural region, none of which was found in the hypervariable region. Only one cluster (amino acids 73-89) was recognized by all human and chimpanzee sera. Clear variation in the immune response was observed between individuals, although no obvious difference in reactivity between acute and chronic cases was observed. Within individual profiles, the reactivity to each peptide cluster and the total number of reactive clusters increased over time.

Alkaline phosphatase and ATPases in brush-border membranes of rat jejunum: distinct effects of divalent cations and of some inhibitors

The effects of divalent cations and of some inhibitors on the activities of alkaline phosphatase and ATPase were examined in rat jejunal brush-border membranes (BBM) isolated by tha Ca(2+)-(BBMCa) or the Mg(2+)-precipitation method (BBMMg). Similar results were found in BBMCa and BBMMg though generally higher in BBMCa. Alkaline phosphatase activity was stimulated by 5 mM MgCl2 (30% to 44%), but not by 5 mM CaCl2 or 0.1 mM ZnCl2, at pH 9.5 or 7.4. ATPase activity was equally stimulated by 5 mM MgCl2 and by 5 mM CaCI2 (about 150%). Alkaline phosphatase activity was significantly inhibited by 1 mM vanadate, 5 mM diamox, 5.0 mM L-leucine and 1 mM theophylline. In contrast, Ca(2+)-ATPase and Mg(2+)-ATPase activities were not depressed by those alkaline phosphatase inhibitors, but were inhibited by 0.1 mM trifluoperazine (more than 70%). 0.1 mM ZnCl2 also appeared to be inhibitory to Ca(2+)-ATPase and Mg(2+)-ATPase, but not to alkaline phosphatase activity even in the presence of Ca2+ and Mg2+. These results suggest that Ca(2+)-ATPase and Mg(2+)-ATPase activities of the rat jejunal BBM are not merely manifestations of alkaline phosphatase, but rather belong to (a) distinct enzyme(s).

[Constituents of the dry roots of Rehmannia glutinosa Libosch]

From the extract of dry roots of Rehmannia glutimosa, fatty acids, palmitic acid, beta-sitosterol, daucosterol and sulfur (Ss) cyclic compound were isolated and identified. The latter four were isolated for the first time.

The effects of rubidium, caesium and quinine on 5-HT-mediated behaviour in rat and mouse--2. Caesium

Rats and mice were given either CsCl (3 mmol/kg, s.c.) or saline (as control), twice daily for 3 days. The administration of tranylcypromine (TCP) (15 mg/kg, i.p.) to rats pretreated with CsCl produced the 5-HT behavioural syndrome. Pretreatment with CsCl also enhanced the syndrome induced by p-chloroamphetamine (3 mg/kg, i.p.) or by TCP (15 mg/kg, i.p.) plus L-tryptophan (50 mg/kg, i.p.). p-Chlorophenylalanine (300 mg/kg, i.p., daily on 2 consecutive days) or (-)-propranolol (20 mg/kg, i.p.), pindolol (4 mg/kg, i.p.) and ritanserin (0.4 mg/kg, s.c.), all prevented the behavioural syndrome induced by CsCl and TCP in rats. Pretreatment of rats with CsCl potentiated the 5-HT syndrome, elicited by the 5-HT agonists, 8-OH-DPAT (0.5 mg/kg, s.c.), 5-MeODMT (2 mg/kg, s.c.) and quipazine (25 mg/kg, i.p.). Pretreatment with CsCl potentiated the 5-HT2-mediated head-twitches in the mouse but had no effects on hypothermia in the mouse induced by 8-OH-DPAT (0.5 mg/kg, s.c.). The rate of synthesis of 5-HT in the whole brain (excluding cerebellum) was enhanced by pretreatment with CsCl. The enhancement of 5-HT neuronal function by caesium may be related to its ability to block K(+)-channels in neuronal membranes.

The effects of rubidium, caesium and quinine on 5-HT-mediated behaviour in rat and mouse--1. Rubidium

The administration of TCP (15 mg/kg, i.p.) to rats pretreated with either intraperitoneal RbCl (3 mmol/kg, twice daily for 5 days) or dietary RbCl (30 mmol/kg diet, for 14 days), resulted in the complete 5-HT behavioural syndrome. Pretreatment with p-chlorophenylalanine (i.p. 300 mg/kg x2) or (-)-propranolol (20 mg/kg, i.p.), pindolol (4 mg/kg, i.p.) and ritanserin (0.4 mg/kg, s.c.) prevented the occurrence of the 5-HT syndrome, produced by dietary RbCl plus TCP. Intraperitoneal administration of RbCl had no effect upon the 5-HT behavioural syndrome, produced by 8-OH-DPAT (0.5 mg/kg, s.c.) or 5-MeODMT (2 mg/kg, i.p.) but enhanced the 5-HT syndrome produced by quipazine (20 mg/kg, i.p.), DOI (8 mg/kg, s.c.), p-chloramphetamine (4 mg/kg, i.p.) or by TCP plus L-tryptophan (50 mg/kg, i.p.) in rats. Dietary administration of RbCl resulted in the enhancement of the 5-HT2-mediated head-twitches in the mouse and the attenuation of hypothermia in the mouse, induced by 8-OH-DPAT (0.5 mg/kg, s.c.). The accumulation of 5-HT (after inhibition of monoamine oxidase) and the rate of synthesis of 5-HT in the whole brain (minus cerebellum) were enhanced by dietary and intraperitoneal administration of RbCl, respectively. The effects of lithium and rubidium, respectively, on 5HT function in brain are compared.

Current advances in magnetic resonance imaging (MRI) in spinal cord trauma: review article

Magnetic resonance (MR) images of 87 patients who had sustained spinal cord injuries during the past 2 years, were analyzed and compared with the corresponding clinical, surgical, and in some cases pathological findings. In addition to the standard MR imaging techniques applied in the spinal cord injuries, we also introduced some recent MRI technical achievements which are anticipated to improve diagnostic accuracy and broaden clinical application of this modality with regard to the spinal cord trauma. The recent technical advancements that we used include image enhancement, fat tissue signal suppression, three-dimensional (3-D) imaging, and magnetic resonance angiography (MRA). The reviewed post traumatic changes disclosed in these MR images were classified in 4 categories: acute, subacute, chronic, and the injury's sequelae. The essential properties of the 4 new imaging advancements are considered in relationship to the gain in diagnostic improvement of MRI of the 4 phases of patients with spinal cord trauma.

The effects of rubidium, caesium and quinine on 5-HT-mediated behaviour in rat and mouse--3. Quinine

It has been shown that caesium, which shares properties with quinine as a K(+)-channel blocker, enhanced 5-HT-mediated behaviour in both rats and mice. It was therefore of interest to investigate the effects of quinine on 5-HT-mediated behaviour in the rat and mouse. Quinine, dose-dependently (ED50 = 5 mg/kg), produced the 5-HT behavioural syndrome in rats pre-treated with tranylcypromine (TCP) (15 mg/kg, i.p.). p-Chlorophenylalanine (i.p., 300 mg/kg x2) or (-)-propranolol (20 mg/kg, i.p.), pindolol (4 mg/kg, i.p.) and ritanserin (0.4 mg/kg, s.c.), all prevented the behavioural syndrome induced by quinine (72 mg/kg, i.p.) plus TCP. The administration of quinine (72 mg/kg, i.p.) enhanced the 5-HT syndrome elicited by p-chloramphetamine (4 mg/kg, i.p.) and the 5-HT agonists, 8-OH-DPAT (0.5 mg/kg, s.c.), 5-MeODMT (2 mg/kg, i.p.), DOI (8 mg/kg, s.c.) and quipazine (25 mg/kg, i.p.) in rats. Pretreatment with quinine also potentiated the 5-HT2-mediated head-twitch in the mouse but had no effect on the hypothermia in the mouse, induced by 8-OH-DPAT (0.5 mg/kg, s.c.). Quinine also enhanced the rate of synthesis of 5-HT in the brain of the rat. On the basis of these findings, together with those in the preceding two papers, it is suggested that the effects of rubidium, caesium and quinine, to enhance differentially various aspects of 5-HT function are mediated by actions on 5-HT-modulated K(+)-channels. This conclusion is also discussed in relation to the actions of lithium and electroconvulsive shock on 5-HT function in brain and the treatment of manic-depressive disease.

[Effect of intraventricular injection of 6-hydroxydopamine on the initiation of hibernation in ground squirrels]

The effect of forced depletion of brain norepinephrine (NE) on the onset of hibernation was observed in the ground squirrel (Citellus dauricus) by intraventricular injection of 6-hydroxydopamine (6-OHDA). The results showed: (1) Intraventricular injection of 100-200 micrograms 6-OHDA, which depleted 50-60% NE, markedly facilitated the onset of hibernation, i.e. the average induction period for hibernation in the treated animals was significantly shorter than that of the natural hibernating animals. (2) The average total torpor time in the treated animals was longer than that of natural hibernating animals. (3) All hibernating animals treated with 6-OHDA were able to wake up from deep hibernation spontaneously and undergo normal hibernation bouts. The results indicate the decrease of NE system activity in brain is one important factor in triggering the onset of hibernation.

Fibroblastoid cells derived from rat bone marrow and lung differ in their pattern of production of hemopoietic stimulators and inhibitors

Blood cells develop in the bone marrow, controlled by a complex network of regulatory factors, some of which originate in the non-hemopoietic stroma. Previously we found that the predominant fibroblastoid (FB) cell growing in primary cultures of rat marrow bears surface antigens different from similar cells derived from certain other tissues. As determined by two monoclonal antibodies, the 'marrow type' is ST3+/ST4-, and the 'peripheral type' is ST3-/ST4+. Here we describe some of the functional differences between these two cell types. After primary cultures were depleted of hemopoietic elements and 'other' type FB, colony-stimulating activity was detected in the conditioned media (CM) of cells derived from marrow (ST3+), but not from lung (ST4+). Conversely, lung FB produced a CM that inhibited the clonogenic growth of normal marrow precursors. This substance (or substances) was produced by lung cells in the absence of exogenous stimulation, but by marrow cells only after they had been cultured in the presence of macrophage-derived products. The inhibitory activity did not have any measurable effect on murine blood cell precursors. We conclude that these isolated antibody-defined fibroblast subpopulations from different organs differ in their capacity to stimulate or inhibit normal hemopoietic precursors.

Central nervous system angiography: safety and predictors of a positive result in 125 consecutive patients evaluated for possible vasculitis

To determine the complication rate of cerebral angiography and to identify variables associated with angiograms positive for vasculitis, we retrospectively evaluated 125 consecutive patients who had angiography because of possible central nervous system (CNS) vasculitis. Sixteen of 125 (12.8%) had angiograms positive for CNS vasculitis. Fourteen (11.5%) experienced a transient and 1 (0.8%) had a persistent neurologic deficit due to angiography. The complication rates between patients who were angiogram positive and angiogram negative did not differ (p greater than 0.05). Two clinical variables were significant risk factors for having an angiogram positive for CNS vasculitis: a preexisting rheumatic disease diagnosis (relative odds 3.39, 95% CI 1.08-10.62, p less than 0.033) and an abnormal lumbar puncture (relative odds 5.50, 95% CI 1.13-26.64, p less than 0.031). We conclude that the risk of persistent neurologic complications from angiography is low in patients who have or are suspected of having CNS vasculitis.

Effectiveness of a gentamicin dosing protocol based on postconceptional age: comparison to published neonatal guidelines

OBJECTIVE

To evaluate the effectiveness of a gentamicin dosing protocol based on postconceptional age in producing therapeutic serum concentrations and to compare the protocol with commonly used gentamicin dosing guidelines.

DESIGN

During the initial three months of this study infants were dosed according to physician discretion (group I). In the subsequent three-month period patients were dosed according to a postconceptional age dosing schedule (group II).

SETTING

Infants were enrolled after being admitted to the Newborn Intensive Care Unit at the University of Miami/Jackson Memorial Medical Center.

PATIENTS

Infants less than 37 weeks gestational age with normal renal function, not receiving indomethacin, and requiring gentamicin treatment were enrolled. Fifty-nine infants were enrolled into group I (median weight 1300 g [range 720-3300]), postconceptional age 29 weeks [26-37]); and 68 infants were enrolled into group II (weight 970 g [530-3000], postconceptional age 29 weeks [24-36]).

INTERVENTION

Patients in group II were dosed according to the following protocol: postconceptional age less than 30 weeks, 3.0 mg/kg q24h, and postconceptional age 30-37 weeks, 2.5 mg/kg q18h. Peak and trough serum gentamicin concentrations were obtained in all study patients. Pharmacokinetic parameters were calculated from measured serum concentrations. Using the calculated pharmacokinetic data, peak and trough serum concentrations were simulated for five published neonatal dosing guidelines and the proposed postconceptional age protocol.

MAIN OUTCOME MEASURES

The number of therapeutic serum gentamicin concentrations resulting from the dosing guidelines studied were compared.

RESULTS

Measured trough concentrations differed significantly between the two groups with 35 percent of patients in group I and 90 percent of patients in group II having trough values less than 2 mg/L (p less than 0.001). There was no significant difference in measured peak concentrations between groups. Simulated trough concentrations were significantly different when postconceptional age dosing was compared with commonly used protocols (p less than 0.0001) with the highest percentage of concentrations less than 2 mg/L (89 percent) resulting from the proposed postconceptional age guidelines.

CONCLUSIONS

These data suggest that the proposed postconceptional age protocol is reproducible and reliable in achieving therapeutic gentamicin serum concentrations in neonates.

The ntrA gene of Agrobacterium tumefaciens: identification, cloning, and phenotype of a site-directed mutant

A 3.6-kb EcoRI fragment containing the ntrA gene of Agrobacterium tumefaciens was cloned by using the homologous ntrA gene of Rhizobium meliloti as a probe. Construction of an ntrA mutant of A. tumefaciens by site-directed insertional mutagenesis demonstrated the requirement of the ntrA gene for nitrate utilization and C4-dicarboxylate transport but not for vir gene expression or tumorigenesis.

Repression of SV40 T oncoprotein expression by DMSO

SV40 large T oncoprotein-transformed murine mesenchymal 3T3 T stem cells (CSV3 cells) can be induced to growth arrest and then differentiate into adipocytes. When differentiation occurs, SV40 T oncoprotein expression is repressed (Estervig et al., J Virol 63:2718, 1989). To determine if repression of T oncoprotein expression can also be induced pharmacologically, the effect of a variety of agents that have been reported to effect differentiation in various cell types but not in 3T3 T or CSV3 cells was tested. This rationale suggests that if any of these agents repress T oncoprotein expression in CSV3 cells, then the results would establish that repression of T oncoprotein expression can be mediated by mechanisms independent of overt differentiation. The results show that dimethylsulfoxide (DMSO) is the only agent tested that represses T oncoprotein expression in CSV3 cells. Repression occurs in a dosage-dependent manner within 24-96 hours after exposure to DMSO. The effect of DMSO on T oncoprotein expression is mediated by posttranslational mechanisms that decrease the stability of the T oncoprotein. DMSO-induced repression of T oncoprotein expression is also associated with reversion of the transformed phenotype in CSV3 cells as demonstrated by the loss of responsiveness to a specific transformation-associated mitogen. These data support the conclusion that the pharmacological repression of T oncoprotein expression represents a form of cancer suppressor activity that can be mediated by a distinct molecular mechanism.

Effects of truncations of the cytoplasmic tail of the luteinizing hormone/chorionic gonadotropin receptor on receptor-mediated hormone internalization

The LH/CG receptor is a member of the family of G protein-coupled receptors and consists of a large N-terminal extracellular domain (which is responsible for binding hormone) attached to a region that spans the plasma membrane seven times, ending with an intracellularly located C-terminus. Binding of LH or human CG (hCG) to the LH/CG receptor causes a stimulation of adenylyl cyclase, presumably via activation of Gs. The binding of hormone also leads to its subsequent internalization by receptor-mediated endocytosis. In order to investigate the role of the cytoplasmic tail of this receptor in these events, we prepared a series of mutants in which progressively larger portions of the cytoplasmic tail were deleted. Deletion of 58 amino acids from the C-terminus, in which only 11 cytoplasmic residues remain, resulted in a receptor that was not expressed on the plasma membrane. Receptors rat LHR (rLHR)-t653 and rLHR-t631, in which 21 or 43 amino acids were removed, respectively, were properly expressed. These results suggest that a region(s) between residues 616 and 631 of the rLH/CG receptor are required for proper insertion and/or targeting of the receptor into the plasma membrane. Cells expressing rLHR-t653 or rLHR-t631 bound hCG with the same high affinity as cells expressing the full-length receptor, and basal levels of cAMP were the same among the cells. However, cells expressing the truncated receptors responded to hCG with approximately 2-fold greater levels of maximal cAMP accumulation than cells expressing the full-length receptor. Deletion of up to 43 amino acids from the C-terminus of the rLH/CG receptor had no deleterious effect on hCG internalization. In fact, mutants lacking 21 and 43 amino acids exhibited progressively faster rates of hCG internalization as compared to the full-length receptor. Once internalized, hCG was also degraded at a faster rate in cells expressing the truncated LH/CG receptors. Since hCG-stimulated cAMP stimulation and hCG internalization are retained by rLHR-t631, it can be concluded that the residues, not necessarily the same, required for these functions reside within the 26 amino acids of the cytoplasmic tail closest to the seventh transmembrane helix and/or residues within the intracellular loops. Our data show, however, that both hCG-stimulated cAMP production and hCG internalization are enhanced by the removal of the distal portion of the cytoplasmic tail.

Preliminary report on seroepidemiology of HCV and HBV infection in northern China

1 141 serum samples from various population groups in north China were examined for C100-3Ab by ELISA. Antibody to C100-3 antigen derived from HCV genome (C100-3A) and HBsAg were measured in 438 normal population in Beijing. The C100-3Ab positive rate was 2.1% and the HBsAg positive rate was 2.5%. There is increased occurrence with age. In 649 cases of chronic liver diseases, the HBsAg positive rate was 87.1% in chronic persistent hepatitis (CPA), 88.8% in chronic active hepatitis (CAH), 64.9% in liver cirrhosis (LC) and 67.3% in hepatocellular carcinoma (HCC). The C100-3Ab positive rate was 10.5% (CPH), 12.1% (CAH), 42.6% (LC) and 38.4% (HCC). It is noteworthy that the C100-3Ab positive rate significantly increased with disease progression from CPH to CAH, LC and HCC. Prevalence of cases positive for both C100-3Ab and HBsAg was 0% in the normal population, 6.7% in CPH, 8.4% in CAH, 31.1% in LC and 28.8% in HCC. Investigation of patients with HCV infection showed that only 36.8% had blood transfusions. HCV and HBV infection may play important pathogenic roles in CPH, CAH, LC and HCC in north China.

The 5'-flanking region of the rat luteinizing hormone/chorionic gonadotropin receptor gene confers Leydig cell expression and negative regulation of gene transcription by 3',5'-cyclic adenosine monophosphate

The LH/CG receptor is a G protein-coupled receptor present on gonadal cells whose levels are modulated by a number of hormones, growth factors, and second messenger analogs. With the recently cloned cDNA for the LH/CG receptor, it has been shown that changes in the levels of the cognate mRNA are involved, at least in part, in the observed changes in receptor density. In order to study the transcriptional regulation of the LH/CG receptor we have isolated a 2-kilobase region of the 5'-flanking region of the rat LH/CG receptor gene and subcloned nucleotide -1 (relative to the translational initiation codon) to -1370 into a luciferase reporter plasmid. We show here that this region of the LH/CG receptor gene is able to enhance luciferase activity in MA-10 cells, a line of Leydig tumor cells that normally express LH/CG receptors, as opposed to human kidney 293 cells, which do not. Furthermore, the addition of 8-bromo-cAMP to MA-10 cells, under conditions known to decrease LH/CG receptor numbers and receptor mRNA levels, decreases the relative luciferase activity to about 26% of control. This decrease in reporter gene activity is severely blunted in a subclone of MA-10 cells with a cAMP-resistant phenotype. Our studies show, for the first time, that sequence(s) present with 1370 base pairs of the translational start site of the rat LH/CG receptor gene are sufficient for conferring expression of this gene in Leydig cells and for the negative modulation of LH/CG receptor gene transcription by high concentrations of cAMP.