Hb San Diego [beta 109(G11)Val-->Met] in an Iranian: further evidence for a mutational hot spot at position 109 of the beta-globin gene.
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Adult↗
Biomedical subjects
L G Adams
Publications and source records attributed to L G Adams.
Effects of dietary protein and calorie restriction in clinically normal cats and in cats with surgically induced chronic renal failure.
To determine the effects of long-term dietary protein restriction in cats with chronic renal failure (CRF), 4 healthy adult cats and 7 cats with surgically induced CRF were fed a high-protein (HP, 51.7% protein) diet and 4 healthy adult cats and 7 cats with surgically induced CRF were fed a low-protein (LP, 27.6% protein) diet for 1 year. Cats with induced CRF that were fed the LP diet had reduced serum urea nitrogen concentrations, despite lower glomerular filtration rates, compared with cats with CRF fed the HP diet. Despite five-sixths reduction in renal mass, reduced glomerular filtration rate, and azotemia, 13 of the 14 cats with induced CRF retained the ability to concentrate urine and produced urine with a specific gravity > 1.035. Cats fed the HP diet consumed significantly more calories than did cats fed the LP diet, presumably because the HP diet was more palatable. As a result of the lower caloric intake in cats fed the LP diet, these cats were protein and calorie restricted, compared with cats fed the HP diet. Cats fed the HP diet weighed significantly more than did cats fed the LP diet. Mean hematocrit and mean serum albumin concentration were significantly lower in control cats and in cats with CRF fed the LP diet, compared with control cats and cats with CRF fed the HP diet. Hypokalemia developed in 4 of 7 cats with CRF fed the HP diet (containing 0.3% potassium); hypokalemia did not develop in control cats fed the same diet or in cats with CRF fed the LP diet containing 0.4% potassium. Excessive kaliuresis, hypomagnesemia, and metabolic acidosis did not appear to contribute to the hypokalemia. Subsequent supplementation of the HP diet with potassium gluconate prevented hypokalemia in cats with CRF.
Acid-Base Equilibrium↗
The long-term culture of bovine monocyte-derived macrophages and their use in the study of intracellular proliferation of Brucella abortus.
Although the immune response to Brucella abortus is multifaceted, the key event in contending with this pathogen appears to be the interaction of the organism with cells of the mononuclear phagocyte system. A cell culture system was developed which allowed the long-term maintenance of blood monocyte-derived macrophages in Teflon culture vessels in a relatively unstimulated state. The assay system was optimized for timing of bacteria-macrophage interaction and numbers of bacteria and macrophages used in each assay. Interaction of B. abortus strain 2308 with bovine mononuclear phagocytes from animals phenotypically resistant and susceptible to infection with B. abortus was investigated. This cell culture and assay system should provide a useful model for the investigation of intracellular parasitism in cattle.
Animals↗
Characterization of the heat shock response in Brucella abortus and isolation of the genes encoding the GroE heat shock proteins.
In an effort to define the heat shock response in the bovine intracellular pathogen Brucella abortus, a rough variant lacking extensive lipopolysaccharide was pulse-labeled with [35S]methionine following exposure to elevated temperatures. The major heat shock proteins observed following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography migrate at 70, 62, 18, and 10 kDa. The maximum response was observed between 42 and 46 degrees C and within 2 to 3 h of the shif in temperature and varied slightly for the different proteins. Accumulation of the 62-kDa heat shock protein (62-kDa Hsp) was observed to continue for up to 5 h following the shift in temperature. In an effort to better define the heat shock response and its potential relationship with protective immunity, genes encoding the major heat shock proteins were isolated from recombinant libraries constructed from B. abortus S19 and S2308 and sequenced. The 62-kDa Hsp shares more than 60% amino acid homology with members of the GroEL family and is immunoprecipitated with polyclonal antibodies to Escherichia coli GroEL and monoclonal antibodies to mycobacterial Hsp 65. Western blot (immunoblot) analysis with pooled sera from vaccinated and infected cattle revealed that the 62-kDa Hsp is a predominantly recognized antigen. The roles of these gene products during environmental stress and in protective immunity against brucellosis are under investigation.
Amino Acid Sequence↗
Virulence associated proteins of Brucella abortus identified by paired two-dimensional gel electrophoretic comparisons of virulent, vaccine and LPS deficient strains.
To identify molecular determinants of virulence, the proteins of Brucella abortus strains 2308 (virulent), S19 (vaccine) and lipopolysaccharide deficient rough mutants derived from each (RB51 and S19M3 respectively) were compared by 2-D gel electrophoresis. A total of 996 proteins were identified on autoradiographs of 2-D gels containing [35S]-labeled proteins from these four strains. Proteins differing qualitatively or quantitatively (greater than or equal to 10X) between 2308 and S19 are implicated in virulence and are identified by Mr and pI. Paired comparisons of proteins present in both 2308 and RB51 and missing in both S19 and M3 were used to make tentative identification of 14 putative virulence proteins representing primary expression of genetic differences between virulent and vaccine strains. 28 proteins and/or core lipopolysaccharide-protein complexes involved in the biosynthesis of lipopolysaccharide were identified by paired comparisons of proteins present in both smooth strains and missing in both rough strains.
Bacterial Proteins↗
Effects of stage of gestation and breed on bovine responses to vaccination with Brucella abortus strain 19.
Eighty-eight cattle were injected SC with 2.5 x 10(8) viable cells of Brucella abortus strain 19. All but 1 heifer became seropositive on the basis of the results of 7 brucellosis tests, and the proportion positive decreased with time. The proportion of cattle that were seropositive during a 20- to 67-week period after vaccination was as follows, in decreasing order: hemolysis-in-gel, 59%; buffered-acid plate antigen, 39%; ELISA, 16%; card, 10%; rivanol, 8%; cold complement-fixation, 7%; and automated complement-fixation, 5%. Using the serologic classification in Uniform Methods and Rules for brucellosis eradication, 7 cattle tested brucellosis-positive (2 suspects and 5 reactors). None of the 27 nonpregnant heifers tested positive. Of 18 heifers that were 84 to 135 days in gestation when vaccinated, 6 (33%) tested positive for brucellosis, compared with 0 of 13 and 1 (3%) of 30 heifers that were 11 to 78 and 145 to 253 days in gestation at vaccination, respectively (X2 = 12.07; 2 df; P less than 0.01). Neither breed (Angus, Hereford, Jersey, and Brahman) nor calf survival was related to brucellosis-positive results. Postpartum milk samples from 61 heifers and 24 tissues from 2 reactor cattle were culture-negative for B abortus.
Animals↗
Comparison of results from five serologic methods used for detecting Brucella abortus antibody activity in coyote sera.
A total of 423 serum samples representing 94 coyotes which were wild trapped in east Texas were used to compare the serologic results from five different methods for detecting antibodies to Brucella abortus. The sera were tested for Brucella spp. antibody activity by the Card (CARD), rivanol precipitation (RIV), standard agglutination tube (SAT), cold complement fixation test (CF), and enzyme linked immunosorbent assay (ELISA) methods. Each serum sample selected for this comparison demonstrated antibody activity by one or more of the five serologic methods. When the serologic results of the five different methods were compared, 143 sera were positive according to the CF test and agreement was 67.1-70.6% with CARD, RIV and SAT. The maximum agreement for CF positive was with CARD (70.6%) and the lowest agreement fro CF negative was also with CARD (56.4%). Agreement among the serologic methods for the SAT positive ranged from 69.1% (CARD) to 72.7% (RIV). Agreement between SAT and ELISA was poor with only 38.1% agreement for SAT positive and 11.3% agreement for SAT negative. Agreement between methods for CARD positive sera was poor, with a low of 43% for both SAT and ELISA, and a high of 55.6% for RIV. Agreement between methods for 149 RIV positive sera was 83.2% for CARD, 67.8% for SAT, 64.4% for CF and only 50.3% for ELISA. Agreement between methods for ELISA positive results ranged from 49.0% for RIV to 62.7% for CARD.(ABSTRACT TRUNCATED AT 250 WORDS)
Animal Diseases↗
SDS-soluble and peptidoglycan-bound proteins in the outer membrane-peptidoglycan complex of Brucella abortus.
Outer membrane-peptidoglycan complex from Brucella abortus was separated from cytoplasmic membrane and cytosol by either sucrose density gradient fractionation or differential (rate) centrifugation of surface labeled cells disrupted by sonication without the use of detergents. The outer membrane-peptidoglycan complex had a buoyant density of 1.22 gm/ml and contained 67 labeled SDS-soluble proteins when examined by SDS-PAGE. Included were four major bands exhibiting molecular masses of 88k, 40k, 35.7k and 26k daltons corresponding to previously described group 1, 2 and 3 outer membrane proteins. Lysozyme treatment of outer membrane-peptidoglycan complex increased its buoyant density to 1.25 gm/ml and released eight additional peptidoglycan-linked proteins.
Animals↗
Effect of modified protein diets in dogs and cats with chronic renal failure: current status.
Studies in rodents indicate that diet influences progression of renal failure. Excessive dietary intakes of protein, fat, energy and phosphorus have been implicated in promoting progression of renal failure, while restriction of some or all of these dietary constituents limits progressive renal injury. Studies confirm that renal failure is progressive in some dogs with moderate-to-advanced renal dysfunction. Recent studies also indicate that unrestricted intakes of protein promotes proteinuria in dogs and cats and glomerular injury in cats.
Animals↗
Brucella abortus in Bison. II. Evaluation of strain 19 vaccination of pregnant cows.
Protection against Brucella abortus induced abortion and infection provided by strain 19 (S19) vaccination was evaluated in American bison (Bison bison). Forty-eight pregnant bison were manually inoculated (MI) with S19 vaccine, 44 were ballistically inoculated (BI) with an absorbable hollow pellet containing lyophilized S19, and 46 were manually injected with buffered saline as non-vaccinated controls (NVC). All bison were Brucella spp. seronegative prior to the experiment, in the second trimester of pregnancy, and were randomly assigned to experimental groups. Approximately 60 days post-vaccination, abortions were observed in the vaccinated bison. Brucella abortus strain 19 was recovered from a bison that had recently aborted, her fetus, and from 11 of 12 other aborted fetuses. Fifty-eight percent (53 of 92) of vaccinated bison aborted, and no abortions were observed in the NVC bison. One cow aborted during her second post-vaccinal pregnancy and S19 was identified from the dam and fetus indicating that chronic S19 infections can occur in bison. Positive antibody titers were present 10 mo post-vaccination in 73% (66 of 91) of the bison. Thirteen mo post-vaccination, 30 MI vaccinates, 27 BI vaccinates, and 30 NVC bison were challenged during the second trimester of pregnancy with 1 x 10(7) CFU of B. abortus strain 2308 via bilateral conjunctival inoculation. Protection against abortion was 67% (P less than or equal to 0.0001) for vaccinated bison compared to 4% in NVC. Protection against B. abortus infection was determined to be 39% (P greater than or equal to 0.001) for vaccinates and 0% (zero of 30) for NCV. Persistent antibody titers, vaccine induced abortions, and chronic S19 infections indicate that the S19 vaccine doses used in this study are not suitable for pregnant bison.
Abortion, Veterinary↗
Effect of stage of gestation on efficacy of Brucella abortus strain-19 vaccination in cattle.
Seventy-nine cattle in all stages of gestation were inoculated with a low dose (2.5 x 10(8) colony-forming units) of Brucella abortus strain 19, then challenge exposed with pathogenic B abortus strain 2308 during the subsequent gestation. A brucellosis case was defined by isolation of strain 2308 from dam or calf samples. Cumulative incidence of brucellosis cases was 48, 33, 25, or 47% for cattle that were, respectively, not pregnant, or 19 to 87, 100 to 167, or 190 to 253 days in gestation at vaccination. The cumulative incidence was 56% in 27 nonvaccinated controls. The 95% confidence intervals for risk ratios included 1 in all cattle, except those that were 100 to 167 days in gestation at vaccination (ie, second trimester); the confidence interval for this group was 0.21 to 0.97. The prevented fraction (1-risk ratio) attributed to strain 19, in ascending order, was 0.14, 0.16, 0.4, or 0.55, respectively, for cattle that were not pregnant, or were 190 to 253, 19 to 87, or 100 to 167 days in gestation at vaccination. Potential confounders of breed, pen effect, and gestation days at challenge exposure did not significantly affect results. Results supported the hypothesis that stage of gestation at vaccination will affect the prevented fraction of brucellosis, or efficacy of strain 19, in cattle vaccinated with a low dose and, therefore, is one factor that may explain variation in strain 19-induced protection.
Animals↗
Comparison of fractional excretion and 24-hour urinary excretion of sodium and potassium in clinically normal cats and cats with induced chronic renal failure.
The influence of induced chronic renal failure on 24-hour urinary excretion and fractional excretion of sodium and potassium was studied in cats. Induction of chronic renal failure significantly increased fractional excretion of potassium (P less than 0.0001) and sodium (P less than 0.05); however, 24-hour urinary excretion of sodium and potassium decreased slightly following induction of chronic renal failure. Fractional excretion and 24-hour urinary excretion of sodium and potassium were compared by linear regression in clinically normal cats, cats with chronic renal failure, and clinically normal and affected cats combined. In clinically normal cats, linear regression revealed only moderate correlation between fractional excretion and 24-hour urinary excretion for sodium and potassium. Linear regression of these same relationships in cats with chronic renal failure, and in clinically normal cats and cats with chronic renal failure combined, indicated low correlation. Fractional excretions of sodium and potassium were not reliable indicators of 24-hour urinary excretion of these electrolytes in cats with chronic renal failure or unknown glomerular filtration rate. Fractional excretion of potassium and sodium correlated only moderately with 24-hour urinary excretion in clinically normal cats.
Animals↗
Production and use of murine monoclonal antibodies reactive with bovine IgM isotype and IgG subisotypes (IgG1, IgG2a and IgG2b) in assessing immunoglobulin levels in serum of cattle.
Utilizing in-vitro and in-vivo immunizations, murine monoclonal antibodies (Mab's) that are specific for bovine immunoglobulin (IG)--IgM isotype and IgG subisotypes (IgG1, IgG2a and IgG2b)--have been produced. These Mab's were used to estimate the quantities of these bovine Ig isotype and IgG subisotypes in the sera of 56 cows and 24 bulls. The cows were all approximately 18 months of age and the bulls ranged from 12 to 18 months in age. The cows and bull were all apparently healthy and unimmunized. The cows were not pregnant and were nulliparous. Some differences were observed between the serum levels of IgM (higher in cows) and IgG1 (higher in bulls). No ready explanation can be offered for these observed differences.
Animals↗
Immunogenicity of subcellular fractions of Brucella abortus: measurement by in vitro lymphocyte proliferative responses.
Five groups of heifers were immunized with various subcellular fractions of Brucella abortus and tested for their responsiveness in lymphocyte proliferative responses in vitro. The five subcellular fractions used as immunogens were: (1) a mixture of recombinant outer membrane proteins fused to Escherichia coli beta-galactosidase, (2) a mixture of outer membrane proteins BaomI, BaomIIB1, and BaomIII1, (3) a mixture of outer membrane proteins 7.5 kDa and 8.8 kDa, (4) a complex of smooth lipopolysaccharide and proteins, and (5) a complex of outer membranes and peptidoglycan (OM-PG complex) from a rough strain. All immunogens were emulsified in adjuvant and administered twice at a 61-day interval. Two other groups of cows were included; one immunized with strain 19 and the other with adjuvant only. Strain 19 and the rough OM-PG complex induced responsiveness in lymphocyte proliferation assays in a high percentage of immunized cows. The smooth lipopolysaccharide-protein complex induced responsiveness in fewer cows. The lowest frequencies of responding cows were found in groups that received either recombinant proteins or purified protein mixtures. Based on these results, we concluded: (1) cellular immunity, as measured by in vitro lymphocyte proliferative responses, can be induced with subcellular fractions of B. abortus and (2) the more complex the immunogen, the greater the frequency of responding cows.
Analysis of Variance↗
Survival of smooth, rough and transposon mutant strains of Brucella abortus in bovine mammary macrophages.
Transposon mutants offer a unique way to evaluate the role of lipopolysaccharide (LPS) by producing a theoretical single-gene difference between the original strain and the transposon mutant strain. Comparative survival of Brucella abortus smooth strain 2308, rough RB51, smooth strain 19, and two transposon mutant strains (rough strain 2308::Tn5 Lac Z [m106] and rough strain 19::Tn5 Lac Z [m3], was tested in restrictive bovine mammary macrophages that were able to effectively reduce the percentage of intracellular bacterial survival and permissive bovine mammary macrophages that were unable to control the intracellular replication of B. abortus. The theoretical single-gene difference between strain 19 and strain 19::Tn5 lac Z [m3] and between smooth virulent strain 2308 and rough transposon mutant 2308::Tn5 lacZ [m106] is likely related to differences in LPS content or structure. Significant (P less than 0.05) reduction in the survival of rough strain 19::Tn5 Lac Z [m3] with no significant reduction in the rough transposon mutant strain 2308::Tn5 lacZ [m106] indicated that at least one factor other than LPS contributes to the intracellular survival of B. abortus in bovine macrophages.
Animals↗
Induction of lymphocyte responsiveness by the outer membrane-peptidoglycan complex of rough strains of Brucella abortus.
The outer membrane-peptidoglycan complex (OM-PG) from rough strains of Brucella abortus was tested for its ability to induce lymphocyte responsiveness in cattle. Six groups of heifers were immunized with varying doses and administration schedules of rough OM-PG and assayed for responsiveness of their lymphocytes in proliferation assays in vitro. All OM-PG preparations were emulsified in a commercial adjuvant for administration. Two other groups of heifers were immunized with strain 19 vaccine or adjuvant alone. Three groups of heifers received two inoculations of OM-PG antigens from a naturally-occurring rough strain at a 57-day interval. The doses of OM-PG given in these three groups were 400 micrograms, 1200 micrograms, and 4000 micrograms at each inoculation. The frequency of cows that responded in lymphocyte proliferation assays increased with the dose of OM-PG given. Two groups received single inoculations of OM-PG, either 2400 micrograms or 8000 micrograms. Although there were responsive cows in these immunization groups, their frequency was lower than in the groups receiving the same total dose in two inoculations. A sixth group of cows was inoculated with OM-PG from a rough transposon mutant of B. abortus, and the frequency of responsive cows in this immunization group was comparable to that of responsive cows immunized with the same dose of OM-PG from the spontaneous rough mutant. In comparisons of cows inoculated with strain 19 to those inoculated with OM-PG preparations, differences were observed in the relative responsiveness of their lymphocytes to whole cells and OM-PG in the in vitro lymphocyte proliferation assays. These differences suggested that lymphocytes stimulated by strain 19 vaccination have different specificities than those stimulated by immunization with OM-PG of rough mutant strains of B. abortus.
Animals↗
Ability of mononuclear phagocytes from cattle naturally resistant or susceptible to brucellosis to control in vitro intracellular survival of Brucella abortus.
The role of bovine mammary macrophages and peripheral blood monocyte-derived macrophages in natural resistance to bovine brucellosis was evaluated. A group of 11 naturally resistant and 10 chronically infected susceptible cows was studied following challenge with Brucella abortus. Macrophages from a greater proportion (P less than 0.026) of naturally resistant cows were significantly superior to macrophages from susceptible cows in their ability to inhibit the in vitro intracellular replication of B. abortus after challenge exposure. Studies of a second group of cows used mammary macrophages from 12 heifers and blood monocyte-derived macrophages from 22 bulls and heifers. These tests were completed before exposure to B. abortus, using mammary macrophages (P less than 0.039) and blood monocyte-derived macrophages (P less than 0.045), and also showed that macrophages from naturally resistant cattle were significantly superior in their ability to control the in vitro intracellular replication of B. abortus. Our data indicate that the mononuclear phagocytes from more than 80% of the resistant cattle controlled intracellular replication of B. abortus significantly better than did mononuclear phagocytes from susceptible cattle. Mononuclear phagocyte function appears to be an important factor in determining natural resistance to bovine brucellosis.
Animals↗
Characterization of a phosphomonoesterase from Brucella abortus.
Brucellae are facultative intracellular bacterial pathogens that reside primarily in cells of the reticuloendothelial system. The high-speed supernatant obtained after centrifuging a suspension of Brucella abortus that had been frozen-thawed and sonicated contained abundant phosphomonoesterase activity, determined by using 4-methylumbelliferylphosphate as the substrate; this enzyme was purified 2,900-fold (yield, 570%) by chromatography on DE-52 cellulose and hydroxylapatite columns and high-performance liquid chromatography-gel filtration. The native enzyme had a molecular mass of 120,000 daltons (+/- 10,000 daltons), as determined by gel filtration chromatography, and resolved into two bands (60,000 and 66,000 daltons) when subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The B. abortus phosphomonoesterase had the following properties: pH optimum, 6.0 to 6.5; isoelectric point, 3.0; substrate specificity, 5'-AMP greater than 3'-AMP greater than 3'-GMP greater than 5'-GDP greater than 5'-CDP greater than 5'-CTP greater than 5'-UPT greater than phosphotyrosine greater than phosphoserine greater than phosphothreonine. The Km for 5'-AMP was 0.37 mM. Phosphatidylinositol 4,5-bisphosphate and myo-inositol 1,3,4-trisphosphate were poor substrates for the B. abortus enzyme. The phosphomonoesterase did not inhibit superoxide anion production by human neutrophils stimulated with formyl-methionyl-leucyl-phenylalanine. The phosphomonoesterase may be one of the bacterial enzymes in the pathway leading to the production of adenine, which is secreted by B. abortus and blocks the activation of neutrophils.
Acid Phosphatase↗