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Biomedical subjects

T A Bell

Publications and source records attributed to T A Bell.

At least 19 recordsLinked to original sources
PubMed1992

Chronic Chlamydia trachomatis infections in infants.

OBJECTIVE: --To study the natural history of Chlamydia trachomatis infections in infants. DESIGN: --Bacteriologic and serologic study of an inception cohort. SETTING: --University of Washington Medical Center, Seattle. PARTICIPANTS: --Twenty-two infants with C trachomatis infections either not treated early in life or recurring after antimicrobial treatment. MAIN OUTCOME MEASURES: --Persistence of infection in various anatomic sites, antibody responses to specific serovars (serologic variants) of C trachomatis, and serovars of isolates from mothers and infants. RESULTS: --The cumulative proportion of infants still infected at the age of 1 year was 35%. Infection persisted in the conjunctiva, nasopharynx, and oropharynx in one child for as long as 866 days (28.5 months), when she was cured by treatment. In none of the infants did serologic tests suggest acquisition of infection other than at birth. Isolates of C trachomatis from mothers and their respective infants were always of the same serovar. CONCLUSIONS: --Many infants infected with C trachomatis at birth remain infected for months or years in the absence of specific antimicrobial therapy. Such infections may be confused with those acquired by sexual abuse.

Antibodies, Bacterial↗
PubMed1992

Microscopic and ultrastructural studies of necrotizing hepatopancreatitis in Pacific white shrimp (Penaeus vannamei) cultured in Texas.

Granulomatous hepatopancreatitis of unknown etiology has been considered an important disease of Texas shrimp mariculture since 1985. Samples of Pacific white shrimp (Penaeus vannamei) were collected during 1986, 1987, and 1990 from three farms and an experimental mariculture facility with histories of production loss and increased mortality rates. Histologic and ultrastructural examination of shrimp from the four sites demonstrated two morphologically distinct, Gram-negative, double-enveloped, intracytoplasmic bacteria in necrotic hepatopancreatic epithelium. The more numerous small, pleomorphic rod as well as the helical organism are both taxonomically unclassifiable. The helical organism lacked ultrastructural characteristics of previously described helical or spiral bacteria. The relationship between the two organisms is unknown, but the pleomorphic rod is thought to play a major role in the disease. The role of a bacterial agent(s) in subsequent disease episodes is suggested by the observation that the use of oxytetracycline-medicated feed resulted in increased production and survival. Hepatopancreatic tubular epithelial necrosis and shrimp mortality correlated directly with the extent of infection by the small pleomorphic rod. Individual discrete bacteria were identified microscopically by Steiner and Steiner's method. Three major developmental stages of the disease were characterized based on the extent and number of hepatopancreatic tubular epithelial cells containing bacteria, the degree of tubular interstitial inflammation, and the extent and chronicity of tubular necrosis. Additional studies are needed to clarify the roles of the different bacteria identified and the potential role of environmental factors on the disease process.

Animals↗
PubMed1991

Cost-effectiveness of prenatal testing for Chlamydia trachomatis.

We investigated the cost-effectiveness of strategies for screening pregnant women for Chlamydia trachomatis. Screening was not cost-effective unless certain conditions were met. Direct antigen testing of all pregnant women would be cost-effective if the test cost less than $6.30 or the prevalence of infection exceeded 6%. However, the positive predictive value of the test was only 51%. Culturing was not cost-effective until the prevalence of infection exceeded 14.8%. If a direct antigen test cost less than $3.90 or prevalence exceeded 8.7%, direct antigen testing of all women and using culture to confirm positive direct antigen tests would be cost-effective. If a direct antigen test cost $8.00 and culture cost $25.00, the excess cost of performing a direct antigen test in all women and confirming positive results with culture would be $2.09 per pregnant woman. Screening all pregnant women for chlamydia is not cost-effective, but the excess cost is modest when direct antigen tests are used.

Chlamydia Infections↗
PubMed1991

The biomechanical effects of deep tissue support as related to brow and facelift procedures.

The adverse effects of increased tension across a healing wound are well known. However, the effect of closing a wound in layers in order to decrease tension on the epidermis has been a source of controversy. It is hypothesized that deep tissue support decreases skin tension upon wound closure. In order to clarify this issue, a two-part study was designed to address the immediate effects of deep tissue support in vitro using fresh-frozen cadavers and in vivo on patients undergoing scheduled surgery. Closing skin tension was measured at standard reference points in coronal brow lift and rhytidectomy procedures performed with and without galeal closure and superficial musculoaponeurotic system (SMAS) procedures, respectively. Deep tissue support was found to significantly (p less than 0.05) decrease skin tension at the time of skin closure at standard reference points in coronal brow lift and rhytidectomy procedures performed on fresh-frozen cadavers. Similar significant (p less than 0.05) decreases in closing skin tension also were found in vivo in patients undergoing similar surgical procedures. Stress relaxation was not found to play a significant role in contributing to this immediate decrease in closing skin tension. It would appear, therefore, that deep tissue support, in the form of galeal closure and an SMAS procedure in coronal brow lift and rhytidectomy procedures, respectively, provides increased viscoelastic support, producing immediate significant decreases in closing skin tension in these procedures. The beneficial effects on wound healing, scar formation, tension-related trophic skin changes, and possible improved long-term results are discussed.

Adult↗
PubMed1990

Chlamydia trachomatis infections in adolescents.

The guidelines of the Centers for Disease Control should be applied with appreciation of their limitations. The serious sequelae of chlamydial infections in young patients warrant vigorous antichlamydial therapy and specific microbiologic diagnosis. Until public health authorities implement control programs, the efforts of individual practitioners will probably be the mainstay of the flight against C. trachomatis.

Adolescent↗
PubMed1990

Endometrial histopathology in patients with culture-proved upper genital tract infection and laparoscopically diagnosed acute salpingitis.

To define and quantitate histologic changes in the endometrium that best correlate with documented upper genital tract infection (UGTI) and laparoscopically diagnosed acute salpingitis, we studied endometrial biopsy specimens from 69 consecutive patients with clinically suspected acute pelvic inflammatory disease (PID) who underwent microbiological evaluation for UGTI and laparoscopic examination for acute salpingitis. Both UGTI and acute laparoscopically confirmed salpingitis were present in 37 patients (54%), UGTI without salpingitis in 1 (1%), salpingitis without UGTI in 11 (16%), and neither UGTI nor salpingitis in 20 (29%). Chlamydia trachomatis or Neisseria gonorrhoeae UGTI was found in 34 women, Escherichia coli in two patients, Peptococcus magnus in one woman, and with Streptococcus agalactiae in one woman. The following features were correlated both with UGTI and with salpingitis: presence of any neutrophils in the endometrial surface epithelium; neutrophils within gland lumens; dense subepithelial stromal lymphocytic infiltration; any stromal plasma cells; and germinal centers containing transformed lymphocytes. The simultaneous presence of five or more neutrophils per X 400 field in endometrial surface epithelium, together with one or more plasma cell per X 120 field in endometrial stroma, was the best predictor of UGTI plus salpingitis. This combination had a sensitivity of 92% and a specificity of 87% for predicting the diagnosis of both UGTI and laparoscopically confirmable acute salpingitis. Prospective studies are needed to assess the usefulness of these criteria.

Acute Disease↗
PubMed1989

Experimental infection of baboons (Papio cynocephalus anubis) with Chlamydia pneumoniae strain 'TWAR'.

Two infant baboons (Papio cynocephalus anubis) were inoculated with Chlamydia pneumoniae strain 'TWAR', one in the conjunctiva, nasopharynx and oropharynx, the other in the trachea. Both remained well during 8 weeks of observation. C. pneumoniae infection persisted for at least 8 weeks after inoculation. Chlamydia pneumoniae seems to be of low virulence in baboons and capable of causing chronic infection.

Animals↗
PubMed1989

Chlamydia trachomatis and Neisseria gonorrhoeae in asymptomatic family planning patients in rural New Mexico.

We tested 98 asymptomatic women seen in state-funded contraception clinics in rural New Mexico. A fluorescein-conjugated monoclonal antibody stain revealed Chlamydia trachomatis infection in 25% of asymptomatic unmarried women and 3% of married women (P = .03). Neisseria gonorrhoeae was detected in only one woman. As in urban clinics providing contraception, the prevalence of gonorrhea is rare in rural New Mexico, but chlamydial infections are common in young unmarried women.

Adolescent↗
PubMed1988

The effect of trimethoprim-polymyxin B sulphate ophthalmic ointment and chloramphenicol ophthalmic ointment on the bacterial flora of the eye when administered to the operated and unoperated eyes of patients undergoing cataract surgery.

Both eyes of patients undergoing cataract surgery were treated with an ointment preparation containing either trimethoprim 5 mg/g and polymyxin B sulphate 10,000 units/g, or chloramphenicol 1%. The antibiotic preparations were administered four times daily on the day prior to surgery, once in the morning prior to surgery and twice daily for fourteen days post-operatively. Cultures from conjunctivae and lid margins were taken prior to treatment, pre-operatively and post-operatively on selected days including the fourteenth post-operative day. The effect of the antibiotics on conjunctival and lid margin flora was determined by enumerating patients with positive cultures prior to treatment which were eradicated following treatment and patients with organisms which were cultured de novo in spite of antibiotic treatment. There was no significant change in the number of patients with organisms isolated from conjunctivae and lid margins (p greater than 0.1 in each case, Sign test) over the sixteen day study period with either treatment. Additionally, when the effect of the two preparations on the number of patients with organisms obtained from conjunctivae and lid margins was compared, there was no significant difference between them (p greater than 0.1 conjunctival cultures, p greater than 0.1 lid margin cultures, Fisher's Exact probability test).

Bacteria↗
PubMed1988

Use of a leukocyte esterase dipstick to detect Chlamydia trachomatis and Neisseria gonorrhoeae urethritis in asymptomatic adolescent male detainees.

We tested 91 asymptomatic adolescent male detainees in a short-stay detention facility in Seattle, Washington for the presence of leukocyte esterase in first-catch urine and for Chlamydia trachomatis and Neisseria gonorrhoeae infection. C. trachomatis was isolated from 10 subjects (11 per cent) and N. gonorrhoeae from five (5 per cent). Dipsticks detected leukocyte esterase in the urine of all 15 subjects with either infection and of 13 subjects with neither infection. Detection of leukocyte esterase was 100 per cent sensitive, 83 per cent specific, and 54 per cent predictive for the presence of either organism.

Adolescent↗
PubMed1987

Delayed appearance of Chlamydia trachomatis infections acquired at birth.

To determine the delay in detectability of Chlamydia trachomatis infections acquired at birth, we serially evaluated 120 infants born vaginally to infected women. Specimens for isolation of Chlamydia were taken from several anatomic sites. Results were analyzed for the age and site of the initial positive culture from each infant. Of 112 infants tested in the first month of life, 22% were culture-positive in the conjunctiva and 25% were positive in the pharynx. Initial positive rectal and vaginal cultures were obtained only in the third and fourth months of life, and all initial vaginal cultures were associated with positive rectal cultures. The latency of C. trachomatis in infants exposed at birth is often more than 1 month and can be longer than 97 days. This latency might be caused by suppression of the growth of the organism by antibodies acquired in utero.

Antibody Formation↗