Comparison of the nucleotide and deduced amino acid sequences of the S genes specified by virulent and avirulent strains of bovine coronaviruses

The entire nucleotide sequences of the spike glycoprotein (S) genes of the highly virulent bovine coronavirus (BCV) strain BCV-LY138, the avirulent BCV-L9 and related Norden Vaccine (BCV-Vaccine) strains were determined using the polymerase chain reaction (PCR) to amplify cDNAs obtained by reverse transcription of viral RNA, and to produce single strand cDNAs for DNA sequencing. The S gene sequences of these viral strains were compared with those of recently published strains BCV-Mebus, BCV-Quebec, and BCV-F15. An open reading frame of 4092 nucleotides, encoding a protein of 1363 amino acid residues, was found in all six strains. Frameshifts and insertions or deletions were not observed except for the BCV-F15. The S gene sequences were more than 98% conserved overall inspite of different origins of the six viruses. There were 45 to 56 nt differences between the virulent and avirulent groups while there were 6 to 14 nt differences among four avirulent strains. Comparison of the deduced amino acid sequences indicated that the S proteins had typical properties of membrane glycoproteins. Nineteen N-linked glycosylation sites were predicted in five strains, and 18 of them were conserved in the avirulent strain BCV-L9. The sequence KRRSRR at the predicted proteolytic cleavage site was identified in five strains while the sequence KRRSVR was found in BCV-F15. Substitutions of few amino acids in the putative fusogenic domains and two prolines at 507 and 567 in the antigenic domains may cause altered immunogenic and other functional properties of the S proteins specified by the virulent and avirulent BCV strains. Nine amino acid substitutions between the virulent and avirulent groups may correlate with BCV virulence.

Infectious mechanisms of enteropathogenic bovine coronaviruses

The primary disease mechanism in infections of calves with enteropathogenic bovine coronaviruses (BCV) involves cytocidal interaction with differentiated enterocytes. Cytopathic expression of BCV infection of cultured cells depends on the viral strain and the cell type. BCV-induced cell fusion occurred under neutral or alkaline but not acidic conditions. Lysosomotropic bases did not significantly reduce virus yield, suggesting that productive BCV infection was not mediated by endocytosis but rather by direct fusion of the viral envelope with the plasma membrane. Trypsin cleavage of the 185 kDa S glycoprotein into 100 and 110 kDa subunits was required for cell fusion and productive infection of cultured BFS cells with the cell-adapted, avirulent strain BCV-L9. This strain has a wide host cell range in vitro while several wild-type, virulent strains were restricted to HRT-18 cells. Antigenic and genomic comparisons of the avirulent and virulent strains revealed corresponding differences. Some monoclonal antibodies against S reacted with both virulent and avirulent strains, while others reacted only with the avirulent strain BCV-L9. Nucleotide sequences of the S genes indicated that amino acid substitutions in cleavage sites, antigenic regions, and putative fusion domains occurred and differentiated BCV strains.

Osteogenesis imperfecta due to recurrent point mutations at CpG dinucleotides in the COL1A1 gene of type I collagen

Most individuals with osteogenesis imperfecta (OI) are heterozygous for dominant mutations in one of the genes that encode the chains of type I collagen. Each of the more than 30 mutations characterized to date has been unique to the affected member(s) of the family. We have determined that two individuals with a progressive deforming variety of OI, OI type III, have the same new dominant mutation [alpha 1(I)gly154 to arg] and that two unrelated infants with perinatal lethal OI, OI type II, share a second new dominant mutation [alpha 1(I)gly1003 to ser]. These mutations occurred at CpG dinucleotides, in a manner consistent with deamination of a methylated cytosine residue, and raise the possibility that CpG dinucleotides are common sites of recurrent mutations in collagen genes. Further, these findings confirm that the OI type-III phenotype, previously thought to be inherited in an autosomal recessive manner, can result from new dominant mutations in the COL1A1 gene of type-I collagen.

Superoxide dismutase decreases mortality, blood pressure, and cerebral blood flow responses induced by acute hypertension in rats

Oxygen radicals are known to be produced by the cerebral vasculature during acute, pressor-induced hypertension and are also known to inactivate endothelium-derived relaxing factor. The objective of our present study was to determine if the oxygen radical scavenger superoxide dismutase (24,000 units/kg plus 1,600 units/kg/min) alters the pressor, cerebral blood flow, and mortality responses to systemic norepinephrine in rats. Increasing doses (0.01-30 micrograms/kg i.v.) of norepinephrine were given by bolus injection to eight rats, and changes in the cortical microcirculatory blood flow were measured by laser-Doppler flowmetry. Superoxide dismutase shifted the norepinephrine-blood pressure and -cerebral blood flow dose-response curves moderately, but significantly, to the right such that it took more norepinephrine to reach a given blood pressure. However, superoxide dismutase had no effect on the autoregulation of cerebral blood flow. Additionally, whereas five (63%) of the eight control rats died after the 10 micrograms/kg norepinephrine dose, all eight rats treated with superoxide dismutase survived this dose. The mechanism by which superoxide dismutase reduced mortality is uncertain. The blood pressure and cerebral blood flow results suggest that superoxide dismutase prevents oxygen radicals from destroying endothelium-derived relaxing factors, which reduce the pressor effects of norepinephrine.

Characterization of a new, potent, immunopathogenic epitope in S-antigen that elicits T cells expressing V beta 8 and V alpha 2-like genes

Experimental autoimmune uveoretinitis (EAU) is a predominantly T cell-mediated autoimmune disease induced in susceptible animals by active immunization with human or bovine retinal S-Ag or by passive transfer of activated S-Ag or peptide-specific CD4+ T cells. During the course of studies aimed at the identification of T cell and B cell recognition sites in bovine and human S-Ag, a new potent uveitogenic region, located near the carboxy terminus of the molecule, was identified and characterized. Analysis of several synthetic peptides from this region showed that a 14 amino acid residue peptide, BSAg339-352, was highly uveitogenic when injected with adjuvants into Lewis rats. A uveitogenic T cell line, R737, was raised by in vitro selection of lymphocytes from animals immunized with peptide BSAg333-352. Northern blot analysis of mRNA from the R737 T cell line was positive for the rat homologs of murine V beta 8 and V alpha 2 T cell receptor gene probes. Whereas peptide BSAg339-352 defined the pathogenic site, nonpathogenic, proliferative sites were found in close physical association. This region is immediately adjacent to previously characterized pathogenic and proliferative sites contained in residues BSAg352-364. These results, as well as our previous observations, show S-Ag to be a complex molecule with several highly conserved amino acid sequences that can elicit pathogenic T cells with restricted T cell receptor V gene usage capable of active and passive elicitation of experimental autoimmune uveoretinitis.

Characterization of a new, potent, immunopathogenic epitope in S-antigen that elicits T cells expressing V beta 8 and V alpha 2-like genes

Experimental autoimmune uveoretinitis (EAU) is a predominantly T cell-mediated autoimmune disease induced in susceptible animals by active immunization with human or bovine retinal S-Ag or by passive transfer of activated S-Ag or peptide-specific CD4+ T cells. During the course of studies aimed at the identification of T cell and B cell recognition sites in bovine and human S-Ag, a new potent uveitogenic region, located near the carboxy terminus of the molecule, was identified and characterized. Analysis of several synthetic peptides from this region showed that a 14 amino acid residue peptide, BSAg339-352, was highly uveitogenic when injected with adjuvants into Lewis rats. A uveitogenic T cell line, R737, was raised by in vitro selection of lymphocytes from animals immunized with peptide BSAg333-352. Northern blot analysis of mRNA from the R737 T cell line was positive for the rat homologs of murine V beta 8 and V alpha 2 T cell receptor gene probes. Whereas peptide BSAg339-352 defined the pathogenic site, nonpathogenic, proliferative sites were found in close physical association. This region is immediately adjacent to previously characterized pathogenic and proliferative sites contained in residues BSAg352-364. These results, as well as our previous observations, show S-Ag to be a complex molecule with several highly conserved amino acid sequences that can elicit pathogenic T cells with restricted T cell receptor V gene usage capable of active and passive elicitation of experimental autoimmune uveoretinitis.

Conserved T cell receptor V gene usage by uveitogenic T cells

Retinal S-antigen is widely used to study the LEW rat model of experimental autoimmune uveoretinitis (EAU). In this report, we have examined the T cell receptor V gene usage of several T cell lines recognizing either pathogenic or nonpathogenic sites on S-antigen to determine whether the V alpha 510 and V beta 510 rat homologues of the murine V alpha 2 and V beta 8 families, respectively, are used by uveitogenic T cells. Using cDNA probes for a LEW rat T cell receptor specific for the encephalitogenic determinant of myelin basic protein, we have found that in the retinal S-antigen/EAU model for autoimmune disease, pathogenicity correlates with usage of those rat V genes. Thus, all of the pathogenic lines were found to express T cell receptors of the V beta 510 and V alpha 510 families; conversely, V beta 510 usage was not detected in any of the nonpathogenic lines. Usage of these V regions has been associated with pathogenicity in the murine and rat models of experimental autoimmune encephalomyelitis, and now with S-antigen-induced EAU.

1-2B7B: monoclonal antibody reacting to the 120 kDa polypeptide component of human epidermal hemidesmosomes

Immunohistochemical and immunochemical analyses were performed on a monoclonal antibody designated 1-2B7B which was derived from immunizing mice with human prostate epithelial tissue. The 1-2B7B antigen was expressed not only along the acinous basement membrane zone (BMZ) of the prostate and testis, but also along the BMZ of the epithelia of several other organs including the skin, oesophagus, urinary bladder, ureter, stomach, intestine and bile duct. The antigenic epitope was not expressed in these tissues of lower mammals. Immunoelectron microscopic studies on normal human skin revealed that the 1-2B7B antigen was localized mainly just beneath the hemidesmosomes of basal keratinocytes, but not beneath melanocytes. Indirect immunofluorescence and immunoelectron microscopic studies on 1 M NaCl-split skin confirmed that this antigen was not separated from the cytoplasmic membrane of basal cells after salt treatment. SDS polyacrylamide gel electrophoresis of immunochemically purified protein from the epidermis demonstrated the molecular weight of the antigen to be 120 kDa. 1-2B7B monoclonal antibody should be a useful probe for studying the pathomechanism of some blistering diseases, as well as the assembly and function of the epidermal-dermal junction.

Immunohistochemical demonstration of cytochrome P-450 monooxygenase in regenerating tracheal epithelium: a recapitulation of fetal development

The cytochrome P-450 monooxygenase enzymes, NADPH-reductase and form 2, were demonstrated immunohistochemically in hamster tracheal epithelium that was regenerating after mechanical injury. Bromodeoxyuridine (BrdU), a thymidine analogue, was used to map the location and extent of the wound sites between 8 and 144 h post-injury. In the control and non-wounded areas of the epithelium, the secretory cells were labelled for the monooxygenase enzymes. Label was heaviest in the apical cytoplasm of these columnar cells. At 8 h, secretory cells at the wound margins migrated to cover the wound sites, becoming progressively flattened. Reaction product for monooxygenase enzymes was strong in these flat cells but immunolabelling for BrdU was very low. At 24 h many cells at the wound sites were labelled for BrdU (indicative of a high rate of cell division). Some cells were labelled for monooxygenase but many were not stained at this time. At 48 and 72 h post-injury, none of the cells within the wound sites (regenerating epithelium) were stained. Immunochemical labelling for the monooxygenase enzymes was restored to the nascent secretory cells as they differentiated in the wound sites, beginning at 96 h post-injury. Labelling was stronger at 120 and 144 h post-injury, comparable to that in the control epithelium. The observations suggest that the monooxygenase enzymes were retained by the secretory cells in the wound sites before they divided but were lost from their progeny. Then, the temporal sequence of monooxygenase expression was similar to the pattern of differentiation of nascent secretory cells during fetal development of the tracheal epithelium.

[An investigation on X-ray features of phalanges unguinal tuberosity for 2292 cases of normal adults]

The phalanges unguinal tuberosity of normal adults are always in different shapes because of many normal variations in anatomy. According to the difference in shape, the authors divided them into three types: smooth type (62.65%), mushroom type (28.40%) and irregular type (8.49%). It seems that the difference in shape forms are related with the person's age. It is of practical importance to distinguish occupational from non-occupational osteolytic lesions of finger's distal end if one bears in mind these normal physiological variations in anatomy.

Superoxide dismutase reduces permeability and edema induced by hypertension in rats

These studies determined whether superoxide dismutase (SOD), an oxygen free-radical scavenger, affects brain and lung vascular protein extravasation and water content after acute hypertension. Hypertensive vascular injury was induced in rats by bolus injection of norepinephrine. Vascular permeability was assessed with 125I-labeled serum albumin and water content determined by wet and dry weight measurement. Pretreatment with SOD prevented or reduced the increase in brain water content and brain and lung protein extravasation caused by hypertension, whereas inactivated SOD had no effect. SOD also reduced mortality caused by acute hypertension. Treatment 30 min after hypertension with SOD or polyethylene glycol-conjugated SOD reduced edema caused by hypertension. In some instances SOD reduced tissue water content and permeability to below normal control levels found in animals without hypertension. These studies show that oxygen radicals contribute to increases in permeability and water content after hypertensive injury and also suggest that oxygen radicals may contribute to regulation of vascular permeability and water content in normal animals.

[Immunogold and immunofluorescence localization of epidermal growth factor receptors on MCF-7 human breast cancer cells]

Immunogold and immunofluorescence staining techniques were used for localization of epidermal growth factor (EGF) receptors on MCF-7 cell membranes. Fluorescence microscopy showed that MCF-7 cells reacted with the monoclonal antibody against EGF receptors and gave positive reaction on the membrane surface. Under electron microscope, the electron-dense gold particles were distributing on the membrane surface including the microvilli. A continued course of internalization of EGF receptors labeled with colloidal gold was observed by electron microscopy. It is considered that one of the mechanisms involving breast cancer MCF-7 cell growth and the stimulating effect on the growth of MCF-7 cells by estradiol is autocrine secretion.

Phorbol ester regulation of terminal deoxynucleotidyl transferase, proliferation, and TcR alpha in a pre-T cell line

Terminal deoxynucleotidyl transferase (TdT) is a template-independent DNA polymerase that is transiently expressed during the normal development of T and B lymphocytes. Phorbol 12-myristate 13-acetate (PMA) has been reported to induce maturation-like changes, including the loss of TdT, in many leukemic cell lines. We investigated the mechanism of TdT repression by PMA in an early thymocyte-like cell line, RPMI 8402. At a concentration of 8 nM, PMA caused both repression of TdT synthesis and arrest of proliferation. At greater concentrations of PMA, these same changes initially occurred, but then cell proliferation resumed, and TdT was reexpressed. At both 8 and 160 nM PMA, TdT biosynthesis and TdT mRNA became undetectable within 8 hours, while cell proliferation and DNA synthesis were not significantly reduced until 16 hours. Growth arrest induced by serum starvation did not result in a similar reduction of TdT RNA even after 48 hours. With 160 nM PMA, TdT mRNA could be detected again by 24 hours, and proliferation resumed. Transcription run-off assays indicated that TdT RNA synthesis ceased within 1 hour after exposure to both 8 and 160 nM PMA. T cell receptor alpha (TcR alpha) RNA was induced when TdT RNA was repressed. TcR beta RNA levels were unchanged, and TcR gamma RNA was up-regulated. TdT gene repression and modulation of cell proliferation as well as induction of TcR gene expression are normal events during intrathymic T cell maturation. This cell model provides a system for analyzing the molecular regulation of these significant developmental events.

Localization of healing tracheal wounds using bromodeoxyuridine immunohistochemistry

Immunohistochemical demonstration of the thymidine analogue bromodeoxyuridine (BrdU) in regenerating cells was useful in determining the size and location of the wounded areas (epithelial and submucosal) during regeneration of the hamster tracheal epithelium, at times late in the healing process (72-144 hr postinjury) when the wound sites and their boundaries were not recognized with certainty in conventionally stained paraffin sections. Cells distant from the wound sites remained unlabelled. The success of this method resulted from prolonged exposure to BrdU released over several hours from a 25mg tablet implanted subcutaneously at 24 hr postwounding at the time when DNA synthesis and cell proliferation are maximal. This simple technique promises to be useful in determining the size and location of wound sites with application to a wide variety of organs and tissues in studies of repair and healing.

Seroprevalence of porcine and human influenza A virus antibodies in pigs between 1986 and 1988 in Hassia

1,268 sera collected from slaughtered pigs in Hassia (FRG) from 1986 to 1988 were tested for antibodies against porcine and human influenza A virus strains using the single radial haemolysis test (SRHT). Antibodies against the porcine strains (subtype H1N1) A/Swine/Arnsberg/1/81, A/Swine/Iowa/15/30 and A/New Jersey/7/76 were detected in 411 (32.4%), 318 (25.1%) and 304 (24.0%) of sera, respectively. Up to 1988 a slight increase (10%) in the seroprevalence to A/Swine/Arnsberg/1/81 was noticed, whereas the results obtained with the other strains showed little variation. Antibodies against the human H1N1 strain A/Singapore/6/86 were only found in sera collected 1987 and 1988 in rates of 1.6% and 3.0%. Serological indication of infections with the human H3N2 strains A/Victoria/1/75, A/Hong Kong/1/68 and A/Philippines/2/82 could be shown in 286 (22.6%), 178 (14.4%) and 135 (10.6%) of the serum samples. Within the three year period the rate of sera positive for antibodies against A/Philippines/2/82 increased from 6.5% to 23.0%, whereas no variation in the rates were found using the other H3N2 strains. Antibodies simultaneously against porcine (H1N1) and human (H3N2) virus strains were detected in 9.9% of all sera tested.

Anaerobic dechlorination of 2,4-dichlorophenol in freshwater sediments in the presence of sulfate

In the presence of added sulfate, 2,4-dichlorophenol and 4-chlorophenol were transformed stoichiometrically to 4-chlorophenol and phenol, respectively, in anaerobic freshwater lake sediments between 18 and 40 degrees C. The concomitantly occurring sulfate reduction reduced the initial sulfate concentration from 25 mM to about 6 to 8 mM and depressed methane formation.

Mutagenic and carcinogenic heterocyclic amines in Chinese cooked foods

Samples of 7 foods commonly eaten in the Northeast of China (i.e. fried and broiled fishes and broiled meat) were tested for mutagenicity on Salmonella typhimurium TA98 with S9 mix. The basic fractions of the samples were mutagenic, inducing 33-2930 revertants/g of cooked food. Fried walleye pollack (a kind of cod fish heated on a stainless steel pan) showed the highest mutagenicity, so attempts were made to isolate mutagens from the basic fraction of this food. The mutagens were purified by treatment with blue cotton and HPLC on a semi-preparative ODS column and analytical cation exchange and ODS columns. 5 mutagens were isolated and identified as 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). 1 g of fried fish was estimated to contain 0.16 ng of IQ, 0.03 ng of MeIQ, 6.44 ng of MeIQx, 0.10 ng of 4,8-DiMeIQx and 69.2 ng of PhIP. MeIQx and PhIP accounted for 24% and 4.7%, respectively, of the total mutagenicity. The other 3 heterocyclic amines were each responsible for only 0.3-1.2% of the total mutagenicity.

[Clinical observation on the changes in plasma cyclic nucleotides in patients with leukemia before and after treatment and their relation to cell-mediated immunity]

Level of plasma cyclic nucleotides was determined in 47 normal subjects and 63 patients with leukemia. Follow-up was carried out in 20 of these patients. The relation between the level of cyclic nucleotides and cell-mediated immunity was studied.

THE RESULTS

There was no significant difference in cyclic adenosine monophosphate (cAMP) between the normal subjects and leukemic patients, whereas cyclic guanosine monophosphate (cGMP) level was markedly elevated and cAMP/cGMP ratio was obviously reduced in the untreated and unrelieved patients. There was no significant difference in the various types of leukemia. In patients with complete remission (CR) after treatment, their cyclic nucleotides were similar to those in normal subjects, but they remained abnormal in patients without clinical remission after treatment. In CR patients treated regularly for half a year, the cGMP level when first diagnosed was lower than that of patients who died soon or were unrelieved. Plasma cGMP level was negatively correlated to E-rosette forming cell (E-RFC) and cAMP/cGMP ratio was positively correlated to E-RFC. These results suggest that the plasma cGMP be used as additional parameter to monitor the treatment response and prognosis. Reduced E-RFC in leukemia may be related to the elevated cGMP and/or lowered cAMP/cGMP ratio.