PubMed Health⌕ Search

Biomedical subjects

R B Simpson

Publications and source records attributed to R B Simpson.

At least 37 records · Page 2Linked to original sources
PubMed1986

Two examples of low ionic strength-dependent autoagglutinins with anti-Pr1 specificity.

Two low ionic strength-dependent autoagglutinins were studied and found to have anti-Pr1 specificity. This specificity was determined by studies with enzyme-treated and neuraminidase-treated human red blood cells (RBCs), animal RBCs and chemically-modified sialoglycoproteins, all suspended in a low ionic strength solution (LISS). Both IgM complement-binding cold agglutinins had a wide thermal range and caused in vitro hemolysis of some LISS-suspended RBCs at 37 degrees C. Compatible blood was found for these patients by using techniques that did not employ LISS.

Agglutination Tests↗
PubMed1986

Dentists who practice with spouses or relatives: a pilot study of practitioners in Iowa.

Of 130 practicing dentists in Iowa surveyed, 73, or 6% of the practicing dentists in that state, responded that they worked with a total of 108 relatives. Half of the relatives were the dentists' spouses. One to ten relatives worked in each office. Overall, the dentists were satisfied with the associations and expected them to continue. Most dentists had informally defined associations, and 10% had written contracts. Dentists named "office policy and organization" most often and "finances" least often as motives behind the associations and "personal growth" most often and "recognition" least often as a satisfaction with the association. The respondents suggested 567 ideas for other dentists considering such associations.

Dentists↗
PubMed1984

Results of analyses and bacterial cultures of urine specimens obtained from clinically normal cats by three methods.

Six urine specimens were obtained from each of 6 male and 6 female cats in a 3-week period. The first and last specimens from each cat were obtained by cystocentesis, 2 were obtained by urethral catheterization, and 2 were caught during voiding stimulated by manual bladder compression. Quantitative urine cultures did not reveal bacteriuria in specimens obtained by cystocentesis, and urinary tract infection did not develop during the study. Bacteria were found in 3 (25%) of 12 urine specimens obtained by catheterization of males and in 1 (8%) of 12 specimens obtained by catheterization of females. Magnitude of bacteriuria in specimens obtained by catheterization was 10 to 1,000 organisms/ml. Bacteria also were found in specimens obtained during voiding. Each of 11 (100%) cleanly caught specimens obtained from males and 7 (58%) of 12 voided specimens from females contained bacteria. Magnitude of bacteriuria in voided specimens was usually 100 to 10,000 organisms/ml, but 3 voided specimens contained greater than 10,000 organisms/ml. Many bacteriuric specimens contained more than 1 type of organism; however, bacteria that might be suspected of causing urinary tract infections in cats were found frequently. Urinalyses were performed on 66 specimens. Completeness of urinalyses depended on the volume of specimens available, but results were normal except for evidence of hematuria in a few specimens obtained by cystocentesis or catheterization. Hematuria was usually mild and was attributed to hemorrhage caused by minor urinary tract trauma during urine collection.

Animals↗
PubMed1983

Coccidioides immitis vaccine: potential of an alkali-soluble, water-soluble cell wall antigen.

C-ASWS-M, the alkali-soluble, water-soluble cell wall antigen of Coccidioides immitis mycelia, was evaluated for its vaccine potential in mice. Vaccination with 0.5-, 1.5-, or 3-mg doses of C-ASWS-M in complete Freund adjuvant provided a significant level of protection against intraperitoneal challenge with 1,500 arthroconidia (P < 0.0001 with each dose). Vaccination with 1 mg of C-ASWS-M protected mice against intranasal challenge with 50 (P < 0.05) and 500 (P < 0.01) arthroconidia, but not against intranasal challenge with 1,500 arthroconidia (P > 0.05).

Animals↗
PubMed1983

Evaluation of the MicroScan Urinary Combo Panel and API 20E system for identification of glucose-nonfermenting gram-negative bacilli isolated from clinical veterinary materials.

Many isolates of glucose-nonfermenting gram-negative bacilli (NFB) cultured from clinical veterinary specimens are not identified because of the large number of identification tests required. We evaluated two commercial identification systems to determine if they could accurately identify NFB isolated from animals. Of 182 strains of NFB, the MicroScan Urinary Combo Panel (MicroScan, Inc., Campbell, Calif.) correctly identified 72%, and the API 20E system (Analytab Products, Plainview, N.Y.) correctly identified 74%. Of the 118 strains of the three most common species of NFB isolated from animals, the MicroScan Urinary Combo Panel identified 86% correctly, and the API 20E system identified 92% correctly. The use of either of these systems could improve the accuracy of identification of NFB from clinical veterinary materials.

Animal Diseases↗
PubMed1983

Fluorine substitution as a probe for the role of the 6-position of benzo[a]pyrene in carcinogenesis.

The tumorigenic activities of benzo[a]pyrene (BP) and 6-fluorobenzo[a]pyrene (6-F-BP) were compared to determine whether an unsubstituted 6-position is important for the carcinogenic effect of BP. Highly purified samples of 6-F-BP and BP had similar activities for the induction of lung adenomas in Swiss Webster mice treated before weaning. The 6-fluoro derivative, however, had about one-half as much activity as BP for the initiation of skin papillomas in CD-1 mice. Similarly, 6-F-BP (approximately equal to 90% purity) had about one-half the activity of BP for the induction of skin tumors in C57BL/6J mice given repetitive treatments of the hydrocarbons and for the induction of sarcomas in C3H/fCum mice given a single sc injection. 6-F-BP (approximately equal to 90% purity) had activity similar to that of BP for induction of sarcomas at the sc injection site in Fischer 344 rats. These results and related data indicate the need for detailed metabolic studies whenever fluorine substitution is used as a probe to assess the role of the unsubstituted position in the carcinogenicity of the parent compound.

Animals↗
PubMed1982

DNA from the A6S/2 crown gall tumor contains scrambled Ti-plasmid sequences near its junctions with plant DNA.

The A6S/2 tumor incited on tobacco by Agrobacterium tumefaciens harboring the octopine-type A6 Ti plasmid contains one insert of Ti-plasmid sequences (the T DNA). This 13 kb insert is derived from a colinear sequence in the Ti plasmid (the T region) and becomes attached to plant DNA in the nucleus of the host cell. We have determined the DNA sequence encompassing the left end of the T region of the A6 Ti plasmid and the corresponding portion of the A6S/2 T DNA. The two sequences are identical for at least 806 bp. To the left of the divergence point, the tumor contains five partially overlapping sequences that are direct or inverted repeats of sequences to the right of the divergence point. The Ti plasmid contains only the right member of each of these repeats. We have also performed heteroduplex studies that indicate that this T DNA has a 520 bp inverted repeat of an internal sequence at the right end near its junction with plant DNA. The repeated sequences near the ends of the T DNA resemble the repeats of adenovirus type 12 sequences found near its junction with host DNA. We discuss data suggesting that the 23 bp to the immediate right of the divergence point of the A6 left junction form a site important in some step in the transfer of T-region DNA from the bacteria to the plant.

Base Sequence↗
PubMed1982

Glucose-nonfermenting Gram-negative bacilli associated with clinical veterinary specimens.

Glucose-nonfermenting gram-negative bacilli (NFB) have been recognized recently as opportunistic pathogens of humans. With few exceptions, strains of NFB have not been considered important enough to be identified when isolated from animals. In this study, all NFB isolated during a 1-year period in a clinical veterinary microbiology laboratory were identified to determine their prevalence. Of the 347 strains of NFB obtained, the most common species were Pseudomonas aeruginosa, Acinetobacter calcoaceticus, Bordetella bronchiseptica, and Pseudomonas pseudoalcaligenes. Of all clinical veterinary specimens submitted for cultures, 10% contained nonfermenters.

Acinetobacter↗
PubMed1982

Effects of washing on the bacterial flora of the stallion's penis.

Six stallions were subjected to extensive cleansing of the penis and prepuce with water, Ivory Soap and water, or Betadine surgical scrub and water. The stallions were all washed for 14 days, and then allowed 14 days respite. This pattern of washing and resting was repeated consecutively. Swabs were taken from all 7 stallions twice weekly and semen was collected once a week for bacteriological examination. All forms of cleansing altered the bacterial flora of the stallion's penis; the Ivory Soap tended to encourage the replacement of the normal flora with coliform organisms, while Betadine favoured the growth of Pseudomonas aeruginosa and Klebsiella spp. This experiment showed that the systematic washing of a stallion's penis will cause the normal flora to be replaced with pathogens and potential pathogens.

Animals↗
PubMed1982

Hypnosis in dental education: a survey of U.S. dental schools, 1980.

This paper reports the results of a 1980 survey of the teaching of hypnosis in U.S. dental schools. Responses were received from 60 dental schools. Information was obtained on hypnosis education in both the predoctoral and postdoctoral curriculums, including what is being taught, how hypnosis education is structured in the curriculum, who is teaching hypnosis, the number of students receiving hypnosis education, and attitudes and policies about hypnosis education. Results of this survey were compared to previous surveys by Parrish (1973) and Scott (1977, for the United Kingdom). The survey reveals a gradual increase in the number of U.S. dental schools teaching hypnosis.

Curriculum↗
PubMed1982

Influence of bacterial products on the motility of stallion spermatozoa.

Sterile filtrates were prepared from equine isolates of Klebsiella pneumoniae (genitalium), Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus zooepidemicus, Streptococcus equisimilis, Actinobacillus equuli, and Corynebacterium equi and mixed individually with extended stallion semen. When diluted in the extended semen the filtrates represented bacterial populations of 0.5 x 10(6), 1 x 10(6), 2 x 10(6) and 4 x 10(6) cells/ml. pH values were recorded for each filtrate. Specimens were monitored for percentage motile spermatozoa at 30-min intervals until they reached 10% or less for 2 consecutive observations. All specimens were maintained at 25 degrees C in a water bath. Ten specimens were examined from each of 5 clinically normal stallions. The major reduction in percentage motile spermatozoa as compared to the control sample occurred before the first observation. From this point the rate of deterioration in motility in the filtrates approximated that of the control. The differences detected between the filtrates and control in percentage motile sperm cells were all statistically significant at P less than 0.01.

Animals↗
PubMed1980

Interaction of the cAMP receptor protein with the lac promoter.

The cyclic AMP receptor protein (CRP) stimulates transcription of the lactose operon by binding to the lac promoter. I have identified those 5-positions of thymines in the promoter that lie close to bound CRP. Although ultraviolet irradiation of DNA with 5-bromouracil substituted in place of thymine normally cleaves the DNA at the bromouracils, a protein bound to the DNA can perturb these cleavages at those locations at which the protein lies close to the bromine. The contacts inferred from this photochemical probe and the results of nucleolytic attack of this complex by exonuclease III support a model where the cyclic AMP receptor protein binds to the promoter making symmetrical contacts with one face of the double helix and then stimulates transcription through contacts with RNA polymerase.

Binding Sites↗
PubMed1980

E. coli RNA polymerase interacts homologously with two different promoters.

We present and review experiments that identify points of close approach of the RNA polymerase to two promoters, lac UV5 and T7 A3. We identify the contacts to the phosphates along the DNA backbone, to the N7s of guanines in the major groove and the N3s of adenines in the minor groove, and to the methyl groups of thymines. These contacts to the two promoters are strikingly homologous in space, as shown on three-dimensional models, and identify major regions of interactions lying on one side of the DNA molecule (at -35 and -16), as well as further areas extending through the Pribnow box. Both promoters are unwound similarly by the polymerase, across a region of about twelve bases extending from the middle of the Pribnow box to just beyond the RNA start site. We discuss the areas of interaction in the context of promoter homologies and promoter mutations. The disposition of the contacts in space suggests a model for the pathway along which the RNA polymerase binds to promoters.

Adenine↗
PubMed1979

Zoonotic diseases in psittacine birds: apparent increased occurrence of chlamydiosis (psittacosis), salmonellosis, and giardiasis.

Between September 1977 and November 1978, chlamydiosis (psittacoisis) was diagnosed in 52 of 128 parrots, 5 of 12 cockatiels, 2 of 5 cockatoos, 3 of 6 macaws, 1 of 22 conures, 2 of 18 lovebirds, and 6 of 76 parakeets; 2 lories and 1 lorikeet were chlamydiosis negative. Two cases of human chlamydiosis were associated with two submissions of parrots subsequently found to have active infection. Twenty parrots (including 13 that were chlamydiosis positive), 2 cockatiels, 1 macaw, 1 lorie, and 1 parakeet yielded salmonella organisms, of which 16 were identified as Salmonella typhimurium, 8 as untypeable monophasic salmonellae of serogroup B, and 1 as S arizonae. Three S typhimurium from parrots that had been treated with chlortetracycline for chlamydiosis were resistant to tetracyclines, streptomycin, and sulfonamides; another isolate was found to be resistant to chloramphenicol only. Severe giardiasis was diagnosed in parakeets originating from six aviaries.

Animals↗
PubMed1979

The molecular topography of RNA polymerase-promoter interaction.

Ultraviolet irradiation forms covalent crosslinks between E. coli RNA polymerase and the lac UV5 promoter substituted with bromouracil in the place of thymine. I have determined the polymerase subunit and the base within the promoter sequence that are joined to each other in two such crosslinks. The sigma and beta subunits of RNA polymerase, respectively, are crosslinked to the third base upstream (-3) and the second base downstream (+3) from the starting point of transcription (+1). Both bases are on the nontemplate strand of the promoter DNA. The location of the beta subunit suggests that it forms at least part of the catalytic site of the enzyme. The disposition of sigma suggests that this subunit plays a direct role in unwinding the DNA at the promoter. The sigma crosslink is close to the "Pribnow Box," which is centered about 10 bases upstream from the RNA start site, contains a striking homology between promoters and is the locus of many promoter mutations.

Base Sequence↗