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Biomedical subjects

W A Stenback

Publications and source records attributed to W A Stenback.

At least 19 recordsLinked to original sources
PubMed1985

Frequency and properties of naturally occurring adherent piliated strains of Haemophilus influenzae type b.

We found that 41 of 75 (55%) children with Haemophilus influenzae type b disease (70 cases of meningitis, 2 of cellulitis, 2 of septic arthritis, and 1 of epiglottitis) and 2 of 120 (1.7%) children with upper respiratory infection were colonized with H. influenzae type b in the nasopharynx (NP). Of these 43 NP strains from children with systemic H. influenzae type b disease, 7 (16%) adhered to human buccal epithelial cells. The strains isolated from the systemic site of all children, including children from whose NP adherent bacteria were isolated, did not adhere to buccal epithelial cells in vitro. Each adherent NP strain had biotype (I), serotype (b), and antibiotic susceptibility (sensitive) similar to that of the corresponding nonadherent systemic isolate. With one exception, all NP-systemic pairs had similar major outer membrane proteins. Six of the seven NP strains had a protein band in the whole cell lysate preparation with a molecular weight between 22,000 and 23,000, which could not be seen in the nonadherent cerebrospinal fluid strains. Electron micrographs of all adherent strains showed that more than 95% of the organisms examined were highly piliated, whereas the nonadherent strains were not piliated. All piliated strains agglutinated human erythrocytes. Adherence to buccal epithelial cells and agglutination of erythrocytes could not be blocked by mannose or alpha-methyl-D-mannoside. We speculate that piliation is not important for NP colonization by H. influenzae type b and that the loss of pili may be required for host invasion.

Adhesiveness↗
PubMed1984

RNA electropherotypes of human rotaviruses from North and South America.

Between April 1979 and December 1982, viral agents were found in 231 of 695 children admitted to the Texas Children's Hospital with gastroenteritis. Electron microscopic analysis showed that rotaviruses were the most common viral agents, and a seasonal pattern of rotavirus disease was observed. The migration patterns of the RNA segments of these rotaviruses on electrophoresis in polyacrylamide gels were compared with those of rotaviruses collected from other areas of the United States of America and from Argentina, Colombia and Mexico. A number of different RNA electropherotypes were found, including some patterns not previously reported.

Child↗
PubMed1983

Antibiotic and nonantibiotic ionophores can alter bacterial adherence to mammalian cells.

Epithelioid (HeLa) and fibroblastic (L) cells in culture incubated for 18 hr with the ionophores amphotericin B and amiloride were noted to bind significantly more and less bacteria, respectively, than control cells incubated without ionophores. These effects were related to dose and incubation length and were present at concentrations approximating those in vivo after administration of maximal doses of these drugs given to humans therapeutically. Electron microscopy of both receptor cell lines revealed increased length and number of cellular projections in the amphotericin-treated cells and flattening and loss of membrane individuality in the amiloride-treated cells. These findings could explain the differences in subsequent bacterial binding. The ionophores nifedipine and verapamil which block calcium transport in cells which have calcium channels did not alter bacterial binding to these receptor cells or bacterial binding to calcium channel-containing myoblasts (in culture). These data suggest that certain ionophores could alter bacterial colonization and infection in the host indirectly by altering bacterial binding; however, the clinical significance of these findings remains to be determined.

Adhesiveness↗
PubMed1982

Zinc and bacterial adherence.

Zinc significantly enhances the ability of piliated Gram-negative and Gram-positive bacteria to attach to HeLa cells. This effect is related to the concentration of zinc and degree of bacterial piliation, and is not present with unpiliated organisms. Bacterial viability is not necessary for this effect, and sulfhydryl blockers decrease the response. These data suggest that zinc can bind to bacterial pili and augment bacterial adherence; in this manner, zinc may act as a virulence factor.

Adhesiveness↗
PubMed1980

The immotile cilia syndrome--one cause of persistent upper respiratory tract infection.

Four patients with persistent recurrent upper respiratory tract infections are presented. Electron microscopic studies of respiratory mucosal biopsies from these patients reveal ultrastructural abnormalities of cilia consisting of partial to complete loss of dynein arms, radial spoke disruption, and compound cilia. The concept of immotile cilia as an important cause of recurrent infections is receiving more attention. This study stresses the need for simple, rapid screening tests for cilial activity followed by electron microscopic evaluation in selected cases.

Biopsy↗
PubMed1979

Attachment of Neisseria gonorrhoeae to human sperm. Microscopical study of trypsin and iron.

Pilated Neisseria gonorrhoeae of colony type 1 (T1) and non-pilated bacteria of colony type 4 (T4) were observed by transmission (TEM) and scanning electron microscopy (SEM). No pili were observed on T4 gonogocci, but two types of pili--straight, type a, and bent, type b--were seen on T1 by TEM. When incubated with human sperum and examined by either TEM or SEM, T1 gonococci were seen to attach by individual pili, by several pili wound together as a rope, or by direct contact. Gonococci from T4 colonies attached only by direct contact. Treatment with typsin (1 mg/ml) damaged or removed pili from gonococci. After incubation with trypsin, attachment of pilated gonococci to sperm was decreased significantly, but such treatment did not affect attachment of non-pilated gonococci. Incubation of gonococci from either colony type in 0.1 mmol/l ferric nitrate, followed by incubation with sperm, significantly increased attachment of only T4 bacteria. No pili were seen on T4 gonococci treated with ferric nitrate; thus, it appears that factors other than pili alone are concerned in attachment of these gonococci to sperm.

Attachment Sites, Microbiological↗
PubMed1978

Virus-specific markers and virus-like particles in cell lines of tumors produced by CELO virus in Syrian golden hamsters.

Cell lines were established from 2 primary hepatocellular carcinomas (HC's) and 3 sarcomas produced in Syrian golden hamsters inoculated as newborns with chicken embryo lethal orphan (CELO) virus. Cell lines from 2 sarcomas (COT, CMT) and 1 HC (CEHEP) produced CELO virus-specific T-antigen. The antigen was not detected in cells of the third sarcoma line (RCT) until they had undergone more than 34 passages in vitro. Although 5-10% of cells in the second HC line (CILT/2) contained T-antigen during early passages, it was not demonstrable after the fifth subculture. Nevertheless, cells of both HC lines possessed CELO virus tumor-specific transplantation antigen. All 5 cell lines also contained hamster type R particles, and both HC lines had type C and intracytoplasmic type A particles. The percentage of carcinoma cells producing type R particles increased during cultivation in vitro, whereas the number of cells with type A particles decreased. Treatment with dibutyryl cyclic AMP and theophylline enhanced the number of cells producing type C particles in 1 HC line and type R particles in 2 sarcoma lines.

Adenoviridae↗
PubMed1975

Oxime derivatives of erythromycin: inhibitors of Rous sarcoma virus reverse transcriptase activity and focus formation.

Bovine adenovirus type 3 (BAV-3), strain WBR-1, quantitatively transforms hamster embryo carcass cells with a maximum efficiency of 4-7 X 10-4 p.f.u./focus-forming units (f.f.u). This frequency is signigicantly inhibited by the presence of 1-8 mM of Ca++. The transformed cells are highly tumourigenic in hamsters and possess T- and tumour-specific transplantation antigens. BAV-3 is one of the most oncogenic of the adenoviruses and an ideal model virus for the study of transformation.

Adenoviridae↗
PubMed1972

Complement-fixing antigens in lymphoid cell lines of American origin.

Lymphoid cell lines from Americans with infectious mononucleosis (Choate, EH IV, and OP), and from a normal American (Cassio), were tested for presence of herpes-like virus by electron microscopy (EM) and immunofluorescence (IF), and for complement-fixing (CF) antigens, using both American and African sera. Whereas earlier tests of seven African (Burkitt) lymphoma cell lines showed an absolute correlation between presence of herpes-like virus and CF reactivity with either African or American sera, the same was not true of the American cell lines. Herpes-like particles were found in the Cassio line by both EM and IF, and in a few cells of the OP line by IF, but not by EM. The virus was not found in the Choate or EH IV lines by either EM or IF. African sera from either normal individuals or patients with Burkitt lymphoma contained CF antibodies to extracts of Cassio and OP cells. Normal American sera contained CF antibodies to these extracts as well as to extracts of Choate cells. The EH IV cell line did not produce CF antigens detectable with either African or American sera. The data indicate that the CF antigens of the herpes virus-negative Choate cell line were serologically distinct from those in Burkitt lines. However, it is possible that the antigens from both sources are related to the presence of the genome of the herpes-like virus.

Antibodies, Neoplasm↗
PubMed1972

Fine structure of Haemophilus vaginalis.

Haemophilus vaginalis 594 has a trilaminar cell wall, ribosomes, a fibrillar nucleoid, and both convoluted and simple mesosome-like bodies. Polar bulbous enlargements of the cell and multiple cross wall formations may explain its pleomorphism.

Cell Division↗
PubMed1971

Complement-fixing antigens in Burkitt lymphoma cell lines.

The complement-fixing (CF) activity of antigens from cultured Burkitt lymphoma cells was determined by using normal American sera as the source of antibody. Approximately 75% of the sera fixed complement with the positive cell lines. These lines contained the herpes-like virus detectable by electron microscopy. The content of CF antigen depended on the cell line used but appeared to be independent of the number of cells which produced Henle's immunofluorescence (IF) antigen. Only sera that reacted in the IF test also contained CF antibodies to the crude cell extracts.

Adult↗