Suppression of apoptosis in normal and neoplastic human B lymphocytes by CD40 ligand is independent of Bc1-2 induction

The tendency of isolated germinal center (GC) B cells to undergo apoptosis was suppressed by recombinant cell-bound CD40 ligand (CD40L): after 2 days at 37 degrees C, > 80% of cells remained viable in the presence of CD40L as compared to < 1% in control cultures. CD40L sustained a high rate of DNA synthesis in GC cells and was more effective than monoclonal antibody to CD40 in this regard. Group I Burkitt lymphoma (BL) cell lines induced to undergo apoptosis with anti-immunoglobulin or calcium ionophore were also protected by CD40L. In BL cells, this route of rescue was not accompanied by induction of Bc1-2 protein, the expression of which has been linked to hemopoietic cell survival. Bc1-2 was induced in GC cells responding to CD40L, but its appearance was a relatively late event not reaching significant levels over controls until day 2 of culture. Thus induction of Bc1-2 appears to be secondary to the survival signal imparted by CD40L. These findings are discussed in relation to a potential role for CD40L in supporting B cell tumors in vivo and the discovery that the molecular defect in the X-linked Hyper-IgM syndrome is targeted to the CD40L gene.

[Alteration of thromboxane A2/prostacyclin and their effect on spinal cord blood flow in experimental spinal cord injury in rats]

In order to document the contribution of Thromboxane (TXA2) and Prostacyclin (PGI2) to the secondary damage following spinal cord injury (SCI) and their effects on spinal cord blood flow (SCBF), the alteration of SCBF, TXB2 and 6-keto-PGF1 alpha concentration in injury site (T13-L1) and adjacent cords (upper: T12, under: L2) were studied using a rat SCI model induced by Allen's weight drop method (50g-cm). The result showed that after SCI the SCBF in injury site significantly reduced during 1-2 hrs and reduced further during 4-8 hrs. The SCBF in adjacent cords also decreased during 4-8 hrs. TXB2 levels significantly increased at 1 hr and reached peak value at 4 hrs. The 6-keto-PGF1 alpha concentration also significantly increased at 1 hr and maintained that level for 24 hrs. The TXB2/6-keto-PGF1 alpha ratio was significantly elevated at 1 hr and reached its peak at 4 hrs after SCI, then gradually decreased to the preinjury level during 8-24 hrs. The negative correlation of SCBF with TXB2 concentration and TXB2/6-keto-PGF1 alpha ratio were appeared. The experimental results indicated that the imbalance of TXB2/6-keto-PGF1 alpha could be the main cause of microcirculatory disturbance and secondary damage in SCI.

A simple method of preparing plant samples for PCR

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Cloning and analysis of the human myocardial Na+/H+ exchanger

The Na+/H+ exchanger is an integral membrane protein that is universally distribute in mammalian tissues and is responsible for intracellular pH regulation. Several isoforms of the Na+/H+ exchanger exist (NHE-1-NHE-4). The first that was cloned is the amiloride sensitive isoform (NHE-1). Using a fragment of the rabbit cardiac Na+/H+ exchanger cDNA clone we isolated and sequenced Na+/H+ exchanger cDNA from a human heart coding for the complete human Na+/H+ exchanger (NHE-1 isoform). Two overlapping cDNA clones were obtained, giving a combined sequence that contained both 3' and 5' untranslated regions. The 5' and 3' untranslated regions proved to be highly homologous to human sequences described earlier but contained some variations that could affect the mRNA stability and/or the efficiency of translation of the Na+/H+ exchanger. Northern blot analysis and reverse transcriptase polymerase chain reaction confirmed the presence of the 5 kb NHE-1 message in primary cultures of isolated myocytes.

Low-power and broadband optical bistability by excitation of surface plasmons in doped polymer film

The low-power and broadband optical bistability in an acceptor-donor-substituted azobenzene-doped polymethyl methacrylate thin film, which relies on the excitation of surface plasmons with a cw laser of several tens of milliwatt power, is studied experimentally and theoretically. The observations on the characteristics of the bistability are essentially consistent with the theoretical predictions.

Oligosaccharide composition of heparin and low-molecular-weight heparins by capillary electrophoresis

The application of capillary electrophoresis to total compositional analysis of heparin and low-molecular-weight heparin samples has been studied. Optimum resolution of 17 defined oligosaccharides was obtained with the buffer system composed of 10 mM sodium borate and 50 mM sodium dodecyl sulfate at pH 8.81 and at a constant voltage of 20 kV. The ratio of oligosaccharide charge to the number of saccharide residues correlated with the migration time. For oligosaccharides having the same charge to saccharide ratio, the larger of the oligosaccharides eluted earlier. A hexasaccharide having a 3-O-sulfated glucosamine residue at the reducing end and arising from heparin's antithrombin III binding site, migrated in an unusual fashion. The limit of oligosaccharide detection was from 600 fmol to 1 pmol. Quantitative analysis could conveniently be performed on 10 pmol of an oligosaccharide sample. Oligosaccharide composition using capillary electrophoresis was obtained by nearly complete depolymerization of heparins with a mixture of heparin lyase I, II, and III. The analysis resulted in 95% mass balance for both heparin and low-molecular-weight heparin. Capillary electropherograms of heparin and different low-molecular-weight heparins depolymerized with heparin lyase I alone showed a high level of structural heterogeneity in the products formed. The oligosaccharide maps thus obtained might find use in fingerprinting the heparin and low-molecular-weight samples.

VACTERL with hydrocephalus: spontaneous chromosome breakage and rearrangement in a family showing apparent sex-linked recessive inheritance

The rate of spontaneous and mitomycin C induced chromosome breakage and sister chromatid exchange (SCE) was studied in three related cases diagnosed with VACTERL-H syndrome. There have been recent reports of sporadic patients with VACTERL-H in whom high rates of chromosome breakage were observed. This has led to the suggestion that some of these patients may represent the severe expression of Fanconi anemia. The pattern of inheritance in our family is highly suggestive of X-linked recessive inheritance supporting the hypothesis that VACTERL-H is, at least in some cases, a syndrome and not an association.

Decreased expression of protooncogenes c-fos, c-myc, and c-jun following polyamine depletion in IEC-6 cells

Direct exposure of small intestinal mucosal cells to luminal polyamines stimulates proliferation. This study tests the hypothesis that the protooncogenes c-fos, c-myc, c-jun, and junB are involved in the mechanism by which polyamines modulate mucosal growth. Studies were conducted in the IEC-6 cell line, derived from rat small intestinal crypt cells. Cells were grown in Dulbecco's minimal essential medium containing 5% dialyzed fetal bovine serum (dFBS) in the presence of absence of alpha-difluoromethylornithine (DFMO), a specific inhibitor of ornithine decarboxylase, which is the rate-limiting enzyme for polyamine synthesis. Cellular polyamine levels, cell growth, and relative abundance of c-fos, c-myc, c-jun, and junB mRNAs, were measured at 1, 2, 4, 6, 8, and 12 days after initial plating. The intracellular polyamines, spermidine and spermine, and their precursor, putrescine, in DFMO-treated cells decreased significantly at 2 days and remained depleted thereafter. Although DFMO profoundly decreased growth and final cell number, both control and DFMO-treated cells entered a plateau phase by 6 days. In control cells, c-myc and c-jun mRNA levels significantly increased on days 4-6 and then returned to a basal level of expression, which was maintained thereafter. c-fos mRNA in quiescent cells after 24 h serum deprivation was significantly stimulated by 5% dFBS, although a steady-state level of c-fos mRNA was undetectable in control cells. Treatment with DFMO not only prevented increased expression of c-myc and c-jun protooncogenes at 4 days, but also significantly reduced steady-state levels of c-myc and c-jun mRNA between 6 and 12 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Conjugal transfer of broad-host-range incompatibility group P and Q plasmids from Escherichia coli to Actinobacillus actinomycetemcomitans

The first example of conjugal transfer of DNA from Escherichia coli to the periodontal pathogen Actinobacillus actinomycetemcomitans is presented. Derivatives of the incompatibility group P (IncP) plasmid RK2 successfully transferred from an E. coli donor to an A. actinomycetemcomitans recipient. The resulting A. actinomycetemcomitans transconjugants transferred the plasmids back to E. coli recipients. The IncP transfer functions were also used in trans to mobilize the IncQ plasmid pBK1 from E. coli to A. actinomycetemcomitans. The IncP and IncQ plasmids both transferred into A. actinomycetemcomitans at high frequencies (0.3 to 0.5 transconjugants per donor) and showed no gross deletions, insertions, or rearrangements. Determinations of MICs of various antibiotics for the A. actinomycetemcomitans transconjugant strains demonstrated the expression of ampicillin, chloramphenicol, and kanamycin resistance determinants.

LY255283, a novel leukotriene B4 receptor antagonist, limits activation of neutrophils and prevents acute lung injury induced by endotoxin in pigs

BACKGROUND

Polymorphonuclear neutrophils (PMNs) have been implicated in the pathogenesis of the adult respiratory distress syndrome (ARDS). Because leukotriene B4 (LTB4) is a potent activator of PMNs, we sought to determine whether LY255283, an LTB4 receptor antagonist, could block PMN activation and lung injury in a porcine model of lipopolysaccharide-induced ARDS.

METHODS

Eighteen hours before being studied, pigs were injected with lipopolysaccharide (20 micrograms/kg). From 0 to 60 minutes, pigs received either Ringer's lactate solution (n = 5) or lipopolysaccharide (250 micrograms/kg). Among the pigs that were infused with lipopolysaccharide, nine received no other treatment, six received a low dose of LY255283 (30 mg/kg loading dose; 3 mg/kg-hr infusion), and six received a high dose of LY255283 (30 mg/kg loading dose; 30 mg/kg-hr). In vivo PMN activation was assessed with an automated chemiluminescence assay wherein results are expressed as CORE/MORE (i.e., the ratio of complement-opsonized zymosan receptor expression on circulating cells [CORE] divided by the maximal complement-opsonized zymosan receptor expression induced by incubating the cells in vitro with LTB4 or platelet-activating factor [MORE]).

RESULTS

In control pigs, lipopolysaccharide induced hypoxemia, pulmonary hypertension, and neutrophil activation (increased CORE/MORE ratio). These changes were attenuated by LY255283, particularly when pigs were infused with the higher dose of the compound. The drug also blunted lipopolysaccharide-induced recruitment of PMNs in pulmonary air spaces, as assessed by bronchoalveolar lavage performed at 240 minutes, although the degree of pulmonary leukosequestration caused by lipopolysaccharide was not affected.

CONCLUSIONS

In a dose-dependent fashion, LY255283 ameliorated lipopolysaccharide-induced ARDS in pigs, possibly by blocking the recruitment of activated PMNs into alveoli.

Characteristics of an Hsp70 homolog localized in higher plant chloroplasts that is similar to DnaK, the Hsp70 of prokaryotes

Members of the 70-kD heat-shock protein (Hsp70) family are important cellular factors that are thought to mediate protein folding and assembly. A chloroplast-localized Hsp70 homolog (Chsp70) was recently identified based on its similarity to DnaK, the Hsp70 homolog of Escherichia coli (D. Amir-Shapira, T. Leustek, B. Dalie, H. Weissbach, N. Brot [1990] Proc Natl Acad Sci USA 87: 1749-1752). To learn more about the function of Chsp70, we purified the protein from Spinacia oleracea chloroplasts by ATP-agarose affinity chromatography. A single, 75,000-D protein was isolated which becomes phosphorylated on a threonine residue when incubated with [gamma-32P]ATP and 10 mM Ca2+, a property similar to DnaK. Chloroplast fractionation and immunoblot analysis showed that Chsp70 is a soluble stromal protein. Chsp70-specific antiserum was used to clone a partial cDNA that shows greater homology with Hsp70 from prokaryotes than with cytoplasmic Hsp70 from eukaryotes. The antiserum and cDNA were used to study Chsp70 expression. Following heat shock of spinach seedlings at 37 degrees C, Chsp70 synthesis increase 12-fold, the level of Chsp70 mRNA increases 5-fold, and the level of Chsp70 protein increases less than 2-fold. Chsp70 is constitutively expressed in all spinach tissues, indicating that it is likely to be localized in all plastid types. The highest levels occur in seeds, leaves, florets, and seedlings grown in the light. Lower levels occur in roots, stems, and etiolated seedlings.

An mRNA putatively coding for an O-methyltransferase accumulates preferentially in maize roots and is located predominantly in the region of the endodermis

ZRP4, a 1.4-kb mRNA that preferentially accumulates in roots of young Zea mays L. plants, was identified by isolation of the corresponding cDNA clone. Genomic Southern analysis indicates that the zrp4 gene is represented once in the corn genome. The deduced ZRP4 polypeptide of 39,558 D is rich in leucine, serine, and alanine. Comparison of the deduced ZRP4 polypeptide sequence to polypeptide sequences of previously cloned plant and animal genes indicates that ZRP4 may be an O-methyltransferase. The ZRP4 mRNA preferentially accumulates in young roots and can be detected only at low levels in leaf, stem, and other shoot organs. ZRP4 mRNA accumulation is developmentally regulated within the root, with very low levels of accumulation in the meristematic region, higher levels in the regions of cell elongation, highest levels in the region of cell maturation, and low levels in the mature regions of the root. ZRP4 mRNA is predominantly located in the endodermis, with lower levels in the exodermis. An intriguing possibility is that the ZRP4 mRNA may code for an O-methyltransferase involved in suberin biosynthesis.

A flower senescence-related mRNA from carnation encodes a novel protein related to enzymes involved in phosphonate biosynthesis

We have isolated a cDNA clone (pSR132) representing a mRNA which accumulates in senescing carnation flower petals in response to ethylene. In vitro translation of RNA selected by hybridization with pSR132 indicated the mRNA encoded a polypeptide of approximately 36 kDa. This was confirmed by DNA sequence analysis, which predicted a peptide composed of 318 amino acids with a calculated molecular weight of 34.1 kDa. Comparison of the predicted peptide sequence of pSR132 with other proteins compiled in the NBRF data base revealed significant homology with carboxyphosphonoenolpyruvate mutase and phosphoenolpyruvate mutase from Streptomyces hygroscopicus and Tetrahymena pyriformis, respectively. These enzymes are involved in the formation of C-P bonds in the biosynthesis of phosphonates. C-P bonds are found in a wide range of organisms, but their presence or formation in higher plants has not been investigated.

[Diagnosis and treatment of infantile endocardial fibroelastosis]

The diagnosis, treatment and etiology of primary infantile endocardial fibroelastosis were studied in 33 patients from 1989 to 1992. Two dimensional echocardiography with Doppler examination showed that the thickness of the endocardium obviously increased and systolic and diastolic functions of the left ventricles were abnormal. Endomyocardial biopsy proved that the endocardium and myocardium under went pathological changes. The virus probe examination of biopsy tissue showed negative results and the effectiveness of immunosuppressive therapy (total effective rate 96%) indicated that this disease is probably of autoimmune etiology. The facts led us to nominate this disease as infantile endomyocardial disease. Besides, the classification, diagnostic criteria, principles of treatment and prognosis of this disease were discussed.

Use of fluorescence in situ hybridization to confirm the interpretation of a balanced complex chromosome rearrangement ascertained through prenatal diagnosis

A balanced complex chromosome rearrangement (BCCR) involving 3 chromosomes with 4 breakpoints, was identified in a 36-yr-old woman who was studied because her fetus was discovered to have an unbalanced reciprocal translocation (7q;10q). Analysis of high resolution bands and the application of fluorescence in situ hybridization has identified the BCCR as der(7)t(7;10)(q21.13;q23.33)ins(21;7)(q21.3;q11.22q21.13), der(10)t(7;10)(q21.13; q23.33), der(21)ins(21;7)(q21.3;q11.22q21.13). Alternate segregation of the BCCR appears to be favoured, and has resulted in two pregnancies with an unbalanced chromosome constitution.

Determination of both mechanical and electronic shifts in cone beam SPECT

The difference between the displacement of the centre of rotation (mechanical shift, MS) and the electronic centring misalignment (electronic shift, ES) in cone beam SPECT is evaluated. A method is proposed to determine both MS and ES using the centroid of a projected point source sampled over 360 degrees and the Marquardt non-linear fitting algorithm. Both shifts are characterized by two orthogonal components. This method is verified using Monte Carlo simulated point source data with different combinations of mechanical and electronic shifts. Both shifts can be determined correctly. We have also applied the proposed method to our cone beam SPECT system to determine both shifts as well as the focal length. The determined ES parameters are then used to correct the projections and the MS parameters are incorporated into a reconstruction algorithm. The point source images are reconstructed and the image resolutions with and without the shift corrections are measured. The experimental results demonstrate that the image resolution is improved after shift corrections. The experimental results also indicate that the shift parameters determined in the same experiment with the point source located at different places are consistent but change from time to time, suggesting that calibration of the system is needed on a periodic basis.

Transplants of immunologically isolated xenogeneic chromaffin cells provide a long-term source of pain-reducing neuroactive substances

Adrenal medullary chromaffin cells are a potential source of neuroactive substances for transplantation into the CNS to alleviate neurochemical deficits. In particular, work in our laboratory has suggested that adrenal medullary transplants in the spinal subarachnoid space can alleviate pain by providing sustained local delivery of catecholamines and opioid peptides. One of the major limitations for clinical application of neural transplantation is the availability of donor material in sufficient quantities. This limitation may be overcome by the use of xenogeneic donors if long-term graft rejection can be prevented. The purpose of this study was to assess whether xenogeneic chromaffin cells immunologically isolated by semipermeable membranes could survive and continue to reduce pain when transplanted into the CNS. Isolated bovine chromaffin cells were encapsulated by semipermeable polymer membranes and implanted into the rat spinal subarachnoid space. Pain sensitivity was assessed at several intervals up to 3 months following implantation. Results indicated that encapsulated bovine chromaffin cell implants, but not empty control capsules, could repeatedly reduce pain sensitivity with nicotine stimulation for the duration of the study. This response was dose related, indicating that pharmacologic integrity of the transplanted chromaffin cells is retained. The analgesia induced by encapsulated chromaffin cell implants could be attenuated by the opiate antagonist naloxone and the alpha-adrenergic antagonist phentolamine, suggesting the involvement of both opioid peptides and catecholamines in mediating this response. In addition, in vitro neurochemical studies of recultured capsules revealed sustained release of Met-enkephalin and catecholamines from encapsulated cells 3 months following implantation into the spinal subarachnoid space.(ABSTRACT TRUNCATED AT 250 WORDS)

Optimization of the synthesis of porcine somatotropin in Escherichia coli

We report on the influence of choice of promoter and RNA polymerase, 5'-untranslated regions and ribosome binding sites, codon usage, leader peptide coding sequences and poly A tail in the 3'-untranslated region on the synthesis of porcine somatotropin (PST) in Escherichia coli. A total of 12 different constructs were tested in this study for the production of porcine somatotropin (PST) in E. coli. Several factors have significant effects on PST synthesis. In the presence of a strong promoter and a strong ribosome binding site, the next most important factor seems to be the combination of sequences at the 5'-end of the mRNA including both the 5'-untranslated region and the start of the coding sequence. Codon usage in the 5'-coding sequence per se is not important in determining the level of PST synthesis where high level expression is achieved from a strong ribosome binding site. However, where low level synthesis of recombinant PST (rPST) is achieved, codon usage in the 5'-coding sequence is important in determining the level of PST synthesis. Leader sequences dramatically reduce the level of PST synthesis. The presence of a poly A tail in the 3'-untranslated region has no significant effect on PST synthesis.

The regulation of the binding affinity of the luteinizing hormone/choriogonadotropin receptor by sodium ions is mediated by a highly conserved aspartate located in the second transmembrane domain of G protein-coupled receptors

Sequence alignment shows that there is a highly conserved aspartate in the second transmembrane helix of virtually all G protein-coupled receptors. A previous study on the alpha 2-adrenergic receptor demonstrated that substitution of this acidic residue for the corresponding amide slightly decreases the affinity of the receptor for agonists and completely abolishes the effect of Na+ on the affinity for agonists. Since we have previously shown that Na+ modulates the binding affinity of the LH/CG receptor for ovine LH (oLH) [but not for human CG (hCG)], the experiments described here were designed to determine if the corresponding residue (D383) of the rat LH/CG receptor also mediates this Na+ effect. We used site-directed mutagenesis to create an LH/CG receptor mutant in which D383 was substituted by N. The wild type and mutant receptor [designated rLHR(D383N)] were expressed in human embryonic kidney 293 cells, and the transfected cells were tested for their ability to bind hCG and oLH in medium containing Na+ or an isoosmolar concentration of an appropriate sodium substitute. The results presented here show that this single point mutation of the LH/CG receptor leads to a slight reduction in affinity for hCG and oLH but completely abolishes the effects of Na+ removal on the affinity for oLH. Thus, regardless of the presence or absence of Na+, cells expressing rLHR(D383N) bind oLH with a low affinity comparable to that of the wild type receptor assayed in the presence of Na+. We also measured the ability of hCG and oLH to increase cAMP accumulation in cells expressing the wild type and mutant receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical observation of immunotherapy in ocular malignant tumors with lymphokine-activated killing (LAK) cell]

In this paper, the authors reported the method of treating ocular malignant tumors with lymphokine-activated killing cells which were induced by rIL-2 in vitro. Among the sixteen cases of ocular tumors, 4 cases of 5 base cell carcinoma (1 case of which was partially extinctive), 4 cases of tarsal gland carcinoma, 2 cases of squamous cell carcinoma and respectively 1 case of retinoblastoma, non-Hodgkin's lymphoma, intraorbital hemangiopericytoma, intraorbital fibrous histiocytomas and hidradenocarcinoma were completely extinctive. The result shows that the immunotherapy method is effective.

Mouse mammary tumor virus associated antigens and superantigens--immuno-molecular correlates of neoplastic progression

There is a large body of literature on immune reactivity to mouse mammary tumor virus (MMTV) during mammary tumor progression. It is a general consensus that MMTV is antigenic and elicits cell-mediated and humoral immune responses. In addition, activation of non-specific inflammatory cells has been observed in various mouse preneoplastic and neoplastic mammary lesions. How these non-conventionally activated inflammatory cells affect tumor progression is a subject of debate. The discovery of MMTV associated superantigens solved certain long standing mysteries and may provide new insight into the cause of these unusual host responses. In this article, we will discuss how superantigen associated secondary immune responses may contribute to mammary tumor progression and the possible impact superantigen may have on specific anti-MMTV reactivity.

[The applicability of a new stable fluorescence reagent CGE (N) for TLC measurements and spectrofluorimetry]

A new stable fluorescent reagent, CGE (N), was designed and synthesized in our laboratory. This paper presents the results of using it to detect a compound having aminogroup. Glycine as an example was derived by using CGE (N), the best condition of derivatisation reaction was pH8, T 50 +/- 1 degree C, and time 3-5 h. Spread agent was CHCl3: CH3OH:CH3COOC2H5: iceHAc (1:3:5:1). Rf of glycine-CGE (N) was 0.45, of which fluorescent spectrum Em was 356nm (at Ex = 277nm). The correlation coefficient between the fluorescent scanning area and quantity was over 0.99, the linear relation retained for 24 h, the detection limit 0.24 microgram, and the linear range 0.24-19.2 micrograms. The data revealed that stability, sensitivity and reproducibility were good. These indicate that CGE(N) is a fine fluorescent reagent for compounds having primary amino-group and this method is reliable.

Multiple second-messenger pathways mediate agonist regulation of muscarinic receptor mRNA expression

Muscarinic acetylcholine receptors in the embryonic chicken heart undergo agonist-induced internalization followed by decreases in both receptor number and mRNA expression. Muscarinic agonists cause both inhibition of adenylyl cyclase and activation of phospholipase C in chick heart cells. Treatment of cells with islet activating protein, which blocks coupling of muscarinic receptors to adenylyl cyclase but not phospholipase C, blocks muscarinic receptor-mediated regulation of receptor mRNA levels. Incubation of cells with the partial agonist pilocarpine, which causes inhibition of adenylyl cyclase but not stimulation of phospholipase C, induces less down-regulation of receptor mRNA levels than agonist which regulate both second-messenger systems. Thus, both second-messenger pathways are required for maximal regulation of muscarinic receptor mRNA levels in response to receptor activation. We also demonstrate that the regulation of receptor mRNA by agonist plays an important role in modulating the rate of recovery of muscarinic acetylcholine receptor number following agonist-induced down-regulation.

Changes in circulating and tissue angiotensin II during acute and chronic stress

Changes of angiotensin II and cAMP in plasma, brain tissue, adrenal gland and cardiovascular tissue during the acute and chronic stress were studied in rats. The acute stress group was subjected to compulsive cold water swimming for 20 min, while the chronic stress group was exposed to an ambient temperature of 4-8 degrees C for 5 days. The results indicated that plasma angiotensin II levels were significantly increased in both stress groups, reaching up to 900% and 134% of the control in the acute and chronic groups, respectively. Angiotensin II contents in the anterior hypothalamus, medulla oblongata, myocardium, vasculature and adrenals were also elevated in both groups. With the exception of the adrenals, the contents of tissue angiotensin II in the chronic stress animals were significantly higher than those of the acute stress animals. In contrast, cAMP levels in plasma and tissue (hypothalamus and adrenals) and corticosterone levels in plasma in the acute stress group were all higher than those in the chronic stress animals, although the levels of the latter group were also increased compared with the control group. These results suggest that circulating and tissue angiotensin II may play an important role in the acute and chronic stress responses and that angiotensin II should be classified as a stress hormone.

Overexpression of wild-type p53 alters growth and differentiation of normal human keratinocytes but not human papillomavirus-expressing cell lines

To examine whether the tumor suppressor gene p53 influences epidermal differentiation, primary cultures of human foreskin keratinocytes and six human papillomavirus (HPV)-positive cell lines were infected with recombinant retroviruses encoding wild-type p53. Overexpression of p53 in organotypic cultures of normal keratinocytes decreased their growth rate and induced premature cell flattening and involucrin expression, a marker of squamous differentiation. However, overexpression of p53 inhibited or delayed production of other epidermal proteins, keratin 10, profilaggrin, and keratinocyte transglutaminase. Furthermore, levels of endogenous cellular p53 dramatically decreased during epidermal differentiation, suggesting that down-regulation of p53 permits complete expression of specific epidermal proteins. Three HPV-immortalized keratinocyte cell lines and three HPV-positive cervical carcinoma-derived cell lines expressed significantly less (< 3-fold) p53 protein than normal keratinocytes. Up-regulation of wild-type p53 (> 5-fold) by retrovirus infection did not significantly inhibit growth or restore normal epithelial differentiation in any line. Thus, overexpression of wild-type p53 can either induce or inhibit expression of specific epidermal proteins in normal keratinocytes but does not reverse immortality or aberrant differentiation of HPV-immortalized or carcinoma-derived cell lines.

Molecular dynamics in refinement against fiber diffraction data

The molecular dynamics (MD) method has been adapted for refinement of the structures of helical macromolecular aggregates aginst X-ray fiber diffraction data. To test the effectiveness of the method, refinements of the tobacco mosaic virus structure were carried out against a set of simulated fiber diffraction intensities using the MD method as well as the conventional restrained least-squares (RLS) method. The MD refinement converged to a very low R factor and produced a structure with generally satisfactory sterochemistry, while the RLS refinemnt was trapped at a local energy minimum with a larger R factor. Results suggest that the effective experimental radius of convergence of the MD method is significantly greater than that of the RLS method. Even when the initial structure is too far from the true structure to allow direct refinement, the MD method is able to find local minima that resemble the true structure sufficiently to allow improved phasing and thus lead to interpretable difference maps for model rebuilding.

Development and histology of fibrous architecture of the fetal temporomandibular joint

The developmental history of the temporomandibular joint (TMJ) was investigated in 10 fetuses of 4 to 10 months of gestational age. The S-type structure of the disc is formed by the following bases: 1) the flat upper and concave lower surfaces of the disc; 2) thinner intermediate zone and thicker anterior and posterior bands; 3) the projection of the articular tuberculum and superoposterior growth of the condyle. The posterolateral part of the disc was the thickest and the corresponding part of the fossa was the deepest. The condyle was originally positioned beneath the part of disc that was considered the main force-bearing area. The distribution and arrangement of elastic and collagen fibers in the disc was proportional to disc function. Gross elastic fibers in the posterolateral part of the posterior band were connected with the upper head of the pterygoideus lateralis muscle fibers running medioanteriorly. They were indicated to be antagonistic with each other. At 4 months of gestational age, a few elastic fibers appeared in the bilaminar region and began to form bundles as the fetus grew. At full-term dense elastic fibers were found in the upper stratum of the bilaminar region.

Intraluminal oxygenation ameliorates ischemia/reperfusion-induced gut mucosal hyperpermeability in pigs

We tested the hypothesis that intraluminal oxygenation can prevent increased gut mucosal permeability to a hydrophilic solute caused by mesenteric ischemia/reperfusion (I/R). Studies were performed using pentobarbital-anesthetized immature pigs. Paired 20 cm segments of ileum were perfused intraluminally at 200 ml/hr with either nitrogenated or oxygenated 37 degrees C Ringer's lactate. Beginning at T = -90 min, fluorescein disodium acetate was infused intravenously (12.5 mg/kg bolus, then 12.5 mg/kg/hr). Permeability was assessed by calculating the plasma-to-lumen clearance of fluorescein. Five pigs were subjected to complete mesenteric ischemia (T = 0-120 min) followed by reperfusion (T = 120-270 min). In nitrogenated segments, I/R resulted in a 1015 +/- 195% increase in fluorescein clearance (P < 0.01 vs baseline). In contrast, the increase in fluorescein clearance induced by I/R in oxygenated segments was only 264 +/- 63% (P < 0.01 vs baseline). Intraluminal oxygenation afforded significant (P < .01) protection against I/R-induced mucosal hyperpermeability at all time points from T = 150-270 min. Histologic sections revealed complete villous epithelial denudation in nitrogenated segments, whereas the mucosal epithelium was largely intact in oxygenated segments. After reperfusion, mucosal ATP levels normalized in oxygenated segments, but there was only partial recovery of ATP levels in nitrogenated segments. These data indicate that intraluminal oxygenation ameliorates mucosal hyperpermeability induced by I/R.

Inhibitors of hematopoietic colonies are produced by certain rat fibroblastoid cell lines and are modulated by corticosteroids

Both stimulatory (CSA) and inhibitory (INH) factors may contribute to hematopoietic regulation, but little is known about how their physiologic balance is maintained. Previously we have shown that antigen-defined fibroblastoid cells cultured from rat lung (ST3-/ST4+) constitutively produce INH, and those derived from bone marrow (ST3+/ST4-) respond to macrophage cytokines to release both CSA and INH into their conditioned media (CM). Here we show that this pattern was maintained in cell strains ("ST3" and "ST4") propagated from the primary cultures, and that the presence of CSA was measured in "ST4" CM if the inhibitory > 100 kd fraction was removed. Two subclones of the "ST3" line, called 2A and 9D, were selected for high or low expression of the ST3 antigen, respectively. Both produced CSA, but only 9D produced the > 100 kd inhibitor. In the CM of cells cultured in the presence of hydrocortisone, there was less INH detected but CSA was not changed. From these data, however, we cannot assess how many individual cell products might be contributing to the INH activity. These results demonstrate that the appearance of inhibitory activity in the growth media differs among fibroblast subpopulations, and that it can be modified by natural regulators such as corticosteroids.

Characterization of a gene that is expressed early in somatic embryogenesis of Daucus carota

The EMB-1 mRNA of carrot (Daucus carota) was isolated as an embryo abundant cDNA clone (T.H. Ulrich, E.S. Wurtele, B.J. Nikolau [1990] Nucleic Acids Res 18: 2826). Northern analyses of RNA isolated from embryos, cultured cells, and a variety of vegetative organs indicate that the EMB-1 mRNA specifically accumulates in embryos, beginning at the early stages of embryo development. In situ hybridization with both zygotic and somatic embryos show that the EMB-1 mRNA begins to accumulate at low levels throughout globular embryos. Accumulation of EMB-1 mRNA increases and becomes more localized as embryos mature; in torpedo embryos, EMB-1 mRNA preferentially accumulates in the meristematic regions, particularly the procambium. The similarity in distribution of EMB-1 mRNA in both zygotic and somatic embryos indicates that much of the spatial pattern of expression of the emb-1 gene is dependent on the developmental program of the carrot embryo and does not require maternal or endosperm factors. The EMB-1 protein (relative molecular weight 9910) is a very hydrophilic protein that is a member of a class of highly conserved proteins (typified also by the Em protein of wheat and the Lea D19 protein of cotton) that may be ubiquitous among angiosperm embryos but whose functions are as yet unknown. The carrot genome appears to contain one or two copies of the emb-1 gene. A 1313-base pair DNA fragment of the carrot genome containing the emb-1 gene was isolated and sequenced. The gene is interrupted by a single intron of 99 base pairs. Primer extension experiments identify two EMB-1 mRNAs, differing by 6 bases at their 5' ends that are transcribed from this gene.

Cloning and characterization of R-PTP-kappa, a new member of the receptor protein tyrosine phosphatase family with a proteolytically cleaved cellular adhesion molecule-like extracellular region

We describe a new member of the receptor protein tyrosine phosphatase family, R-PTP-kappa, cDNA cloning predicts that R-PTP-kappa is synthesized from a precursor protein of 1,457 amino acids. Its intracellular domain displays the classical tandemly repeated protein tyrosine phosphatase homology, separated from the transmembrane segment by an uncharacteristically large juxta-membrane region. The extracellular domain of the R-PTP-kappa precursor protein contains an immunoglobulin-like domain and four fibronectin type III-like repeats, preceded by a signal peptide and a region of about 150 amino acids with similarity to the Xenopus A5 antigen, a putative neuronal recognition molecule (S. Takagi, T. Hsrata, K. Agata, M. Mochii, G. Eguchi, and H. Fujisawa, Neuron 7:295-307, 1991). Antibodies directed against the intra- and extracellular domains reveal that the R-PTP-kappa precursor protein undergoes proteolytic processing, following which both cleavage products remain associated. By site-directed mutagenesis, the likely cleavage site was shown to be a consensus sequence for cleavage by the processing endopeptidase furin, located in the fourth fibronectin type III-like repeat. In situ hybridization analysis indicates that expression of R-PTP-kappa in the central nervous system is developmentally regulated, with highest expression seen in actively developing areas and, in the adult, in areas capable of developmental plasticity such as the hippocampal formation and cerebral cortex. The mouse R-PTP-kappa gene maps to chromosome 10, at approximately 21 centimorgans from the centromere.

7S nerve growth factor has different biological activity from 2.5S nerve growth factor in vitro

It is considered that two molecular forms of nerve growth factor (NGF), that is 7S NGF and 2.5S NGF have the identical neurotrophic effect on neurons. We now report that 7S NGF has different biological activities from 2.5S NGF in vitro. 7S NGF could promote the survival and neurite outgrowth of neurons from newborn rat hippocampus, cortex and cerebellum and stimulate the proliferation of astrocytes in vitro, but 2.5S NGF had no such effect.

Dynamic changes in hypothalamic angiotensin II levels and release in association with progesterone-induced luteinizing hormone surge

To test the hypothesis that brain angiotensin II (Ang II) may be involved in the preovulatory release of LH on proestrus, we evaluated the pattern of changes in hypothalamic Ang II levels and release in ovariectomized (ovx) rats treated sequentially with estrogen and progesterone. This is an experimental paradigm that reliably evokes dynamic changes in hypothalamic LHRH levels in association with LH hypersecretion, simulating the LH surge on proestrus. Rats were ovx and after 4 weeks received estradiol benzoate followed by progesterone 2 days later at 1000 h. We observed that in these progesterone-treated rats, serum LH levels were low until 1400 h, but thereafter, the rate of LH secretion increased and remained elevated at 1600 h when the experiment was terminated. In these rats, hypothalamic Ang II levels increased abruptly at 1330 h and returned rapidly to baseline levels before the onset of LH surge. Also, a similar pattern in hypothalamic Ang II levels occurred at 1500 h with the rise and peak serum LH levels in the late afternoon. In the second experiment, Ang II levels in the cerebrospinal fluid (CSF) of rats similarly pretreated with ovarian steroids were evaluated. Again, CSF Ang II levels rose abruptly to a peak at 1330 h and returned to baseline range preceding the expected rise in serum LH. Thereafter, no further change in CSF Ang II levels was detected during the period of LH hypersecretion. In the third experiment, perfusates were collected from a push-pull cannula aimed at the paraventricular nucleus in ovx rats similarly treated with ovarian steroids. A peak of Ang II was observed at 1330 h and a later peak at 1430 h. A comparison with LH profiles indicated that these peaks in Ang II levels were evident before and during the LH surge. Thus, in three separate experiments, the results showed that rapid dynamic changes in hypothalamic Ang II levels and release occur in association with the progesterone-induced LH surge in estrogen-primed ovx rats. These findings support the previous observations that Ang II can stimulate LHRH and LH release. Since similar, temporally correlated changes occur in hypothalamic neuropeptide Y and LHRH, the peptides involved in the induction of LH surge, these results are in agreement with the hypothesis that Ang II-expressing neurons may play an important role in the hypothalamic circuitry responsible for stimulation of LH surge in ovarian steroid-treated ovx rats.

Tight single-stranded DNA knots

Trefoil (3(1)) and figure-8 (4(1)) knots have been synthesized from DNA molecules containing two single-turn helical domains, linked by four oligodeoxythymidine linkers. Both topologies are derived from the same DNA molecule. The tightest knots are fashioned by minimizing the lengths of the linkers. The shortest equal-length linkers from which a trefoil knot can be made readily are seven nucleotides long, in a 74-nucleotide molecule, whereas those in the shortest figure-8 knot are six nucleotides long, in a 70-nucleotide molecule. In addition to these limiting knots, other knots containing 80, 88, 96 and 104 nucleotides have been constructed. The mobilities of these molecules on denaturing gels show the conventional logarithmic dependence on length. Ferguson analysis of their mobilities indicates a linear dependence of surface area on length. The 80-mer trefoil knot is the tightest molecule that can be restricted in both domains.

N-3 fatty acids stimulate intracellular degradation of apoprotein B in rat hepatocytes

When rat hepatocytes were incubated with albumin complexed to the n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), rather than to oleic acid (OA), the secretion of newly synthesized apoprotein B100 (apoB100) or B48 (apoB48) was reduced, despite stimulation of cellular triglyceride synthesis by all three fatty acids. When pulse-chase studies of apoB synthesis and secretion were performed in the presence of OA, EPA, or DHA, there were no significant changes in the initial synthetic rates of either apoB species. However, during the chase period, the total recovery of labeled apoB100 and apoB48 from the cell and medium was less in the n-3 fatty acid groups, so that by 150 min, approximately half as much labeled apoB was recovered as in the OA group. Overall, the decreased accumulation in medium of labeled apoB in the presence of EPA and DHA could be quantitatively accounted for by increased degradation of intracellular apoB. Thus, in the primary hepatocyte, apoB degradation is not constitutive, but can be regulated by n-3 fatty acids.

Effect of granulocyte colony-stimulating factor on systemic and pulmonary responses to endotoxin in pigs

Granulocyte colony-stimulating factor (G-CSF) stimulates the production and function of neutrophils (PMNs). Administration of G-CSF to non-neutropenic animals has been shown to improve survival in experimental models of infection, but PMNs have been implicated as mediators of acute lung injury induced by lipopolysaccharide (LPS) or bacteremia. Thus G-CSF-induced neutrophilia might be deleterious in sepsis. To investigate this possibility, we studied four groups of pigs: G+E50 (n = 6) were pretreated for 5 days with recombinant bovine (rb) G-CSF (5 micrograms/kg/day) and then challenged with LPS (50 micrograms/kg); NS+E50 (n = 6) were similarly pretreated with saline and challenged with LPS (50 micrograms/kg); E250 (n = 6) were not pretreated and were infused with a larger dose of LPS (250 micrograms/kg); RL (n = 7) were controls infused with lactated Ringer's solution. Pretreatment with rbG-CSF increased the peripheral absolute neutrophil count approximately fivefold (p < 0.05 vs. RL group). Comparisons of the NS+E50 and G+E50 groups showed that pretreatment with rhG-CSF did not affect LPS-induced alterations in mean arterial blood pressure or arterial oxygenation. Indices of pulmonary injury also were similar in these two groups, although pulmonary edema and protein leakage into alveoli were greater in the E250 group. We conclude that G-CSF-induced neutrophilia does not adversely effect physiologic responses to LPS in pigs.

Production and characterization of antibodies specific for the imidazoline receptor protein

Polyclonal antibodies were raised in rabbits against a 70-kDa ligand-binding protein of the imidazoline receptor purified from solubilized bovine adrenal chromaffin cell membranes by ligand affinity chromatography. The antibodies labeled a single protein (approximately 70 kDa) in Western blots of bovine adrenal chromaffin cell membranes, inhibited 40% of specific [3H]idazoxan binding to imidazoline receptors in chromaffin cell membranes, and specifically immunoprecipitated 75% of all imidazoline-binding activity of solubilized chromaffin cell membrane proteins. The antibodies specifically immunostained heterogeneous subsets of cultured bovine chromaffin cells. They stained subpopulations of chromaffin cells of rat adrenal medulla but not the cells of adrenal cortex. We conclude that the antibodies recognize with high specificity and selectivity a approximately 70-kDa binding protein associated with or representing the imidazoline receptor that is expressed in mammalian species. Highly specific antibodies against the imidazoline receptor protein will permit mapping of the distribution of imidazoline receptors in brain and periphery and also may be useful as probes in cloning genes encoding the imidazoline receptors.

[Experimental study on the Biomaterial/Porous Titanium composite dental implants]

This study investigated the tissue compatibility of bone morphogenetic protein (BMP) /biologic ceramic/porous titanium implant,BMP/porous titanium implant,biologic ceramic/porous titanium implant and porous titanium implant by LM,SEM,EDXA.The results showed that the new bone formation and new bone mature were earlier in the BMP composite implants treated group.BMP uncomposite implants had no evident difference in the time of new bone formation, but the interface bonding ways had significant difference.

Regulation of differentiation, proliferation and cancer suppressor activity

This review suggests that carcinogenesis is linked to defects in linkages between cellular differentiation and regulation of cell proliferation. These linkages are discussed in terms of terminal and nonterminal states of differentiation and their relationship to the control of proliferation. The ability of differentiation to regulate proliferation potential proteins and cancer suppressor genes is also discussed, because these mechanisms may be important for cancer prevention and therapy.

[Study of antibody against protein in human allografts of decalcified bones]

The result of study on antibody against protein in human allograft of decalcified bones was reported in this paper. 50 cases with allografts of decalcified bones were detected for sero-antibodies by indirect method of ELISA. The antigens used were extracted protein from the human decalcified bones. Among them, 32 cases showed positive reaction including complete bone graft healing in 30 cases, incomplete healing in one and failed in one cases success rate 98% The other 18 cases showed negative reaction. Neither the Positivith nor the titer of sero-antibody interfered with the healing of allograft.

Phase variation in Xenorhabdus luminescens: cloning and sequencing of the lipase gene and analysis of its expression in primary and secondary phases of the bacterium

The phenomenon of phase variation in the insect-pathogenic bacterium Xenorhabdus luminescens was investigated. Differential activity of the lipase enzyme (EC 3.1.1.3) was observed between the two phases of the bacteria. The enzyme was found to be secreted into the culture medium, and about five to six times greater specific activity was secreted by the primary phase than by the secondary form. The lipase gene (lip-1) was cloned and sequenced. The data imply that there is only a single Tween 80-utilizing lipase gene in X. luminescens K122. The sequence revealed a translation product of 645 amino acids, from which a hydrophobic leader sequence of 24 amino acids is removed during processing. The structure of the gene was shown to be the same in the primary and secondary forms of X. luminescens. In addition, transcription was found to start at the same position, 169 bp upstream of the translation initiation codon, in the two forms of the bacteria. Equal amounts of lipase RNA accumulated in the two forms, and at least as much lipase protein was secreted by the secondary form as by the primary. This suggests that the difference in specific activity between the enzymes secreted by the two phases probably arises from a posttranslational type of regulation.