Search PubMed⌕ Search

Biomedical subjects

C E Stevens

Publications and source records attributed to C E Stevens.

At least 73 records · Page 4Linked to original sources
PubMed1991

Canine BFU-e progenitors: adaptation of a reproducible assay and anatomical distribution.

In vitro cloning assays are used increasingly in investigative hematotoxicology and in screening candidate compounds for their hematotoxic potential. To expand these applications, a practical cloning assay for erythroid burst-forming units (BFU-e) that uses a microplasma clot (MPC) system was adapted to the dog, a species used extensively in experimental hematology and drug development. This system offers the advantage over the methylcellulose and soft agar culture systems of allowing specimen fixation and, therefore, morphological and cytochemical evaluation. The distribution of BFU-e among various anatomic sites was assessed using the MPC cloning system, which was modified to optimize the BFU-e growth. BFU-e growth required only erythropoietin (Epo) in the culture medium and there was no need for an exogenous source of burst-promoting activity (BPA). The cloning efficiency was linearly proportional to the plating concentrations of Epo and marrow mononuclear cells (MMC) over a range of 0 to 3 U Epo and 1 x 10(5) to 3 x 10(5) MMC per ml of culture, respectively. Increases in concentrations of Epo and MMC beyond these levels were not associated with linear growth. The addition of transferrin and spleen-conditioned medium containing a mixture of growth factors (including BPA) reduced BFU-e growth. The relative concentration of BFU-e was comparable among samples collected from the iliac crest, femur, and humerus. Serial cultures performed on individual dogs were highly reproducible and there was little variation in BFU-e activity among dogs of comparable age. It was concluded that the MPC system is a practical and reproducible cloning system for early (BFU-e), as well as late erythroid colony-forming units (CFU-e) in the dog. The concentration of BFU-e appears comparable throughout the active marrow; therefore, various anatomic sites can be used interchangeably for serial quantitative analysis of this progenitor.

Animals↗
PubMed1991

Microbiological, epidemiological and clinical correlates of vaginal colonisation by Mobiluncus species.

The microbiological and epidemiological correlates of vaginal colonisation by Mobiluncus species were examined among randomly selected women attending a sexually transmitted disease (STD) clinic. Women positive for Trichomonas vaginalis were excluded. Mobiluncus spp. were detected by Gram stained vaginal smear in 21% of 633 STD clinic patients, including 53% of those with and 4% of those without bacterial vaginosis (BV), as diagnosed by clinical criteria. Gardnerella vaginalis and Mycoplasma hominis detected by vaginal culture and Mobiluncus detected by vaginal Gram stain were each independently associated with BV after adjusting by logistic regression for the presence of sexually transmitted disease pathogens, gravidity, parity and number of lifetime sexual partners (p less than 0.001 for each organism). Bacterial vaginosis was negatively correlated with isolation of lactobacilli, yeast and herpes simplex virus. After adjusting for presence or absence of BV, women with Mobiluncus were more likely to harbour G vaginalis (odds ratio 5.6, 95% confidence interval 1.6-19.5), M hominis (OR 3.7, 95% CI 2.0-7.0) and Neisseria gonorrhoeae (OR 2.9, 95% CI 1.4-6.0) and less likely to harbour vaginal yeast (OR 0.4, 95% CI 0.2-1.0); were more likely to be black (OR 2.7, 95% CI 1.5-4.6), and to have been pregnant (OR 1.8, 95% CI 1.1-3.1); but after the adjustment for BV, vaginal colonisation by Mobiluncus was not associated with symptoms of odour, abdominal pain, menstrual irregularities, or with adnexal tenderness. In summary, Mobiluncus, Gardnerella vaginalis and Mycoplasma hominis were independently associated with a clinical diagnosis of bacterial vaginosis, and Mobiluncus was further associated with the presence of BV-associated microorganisms (M hominis and G vaginalis), N gonorrhoeae, black race, and gravidity.

Adult↗
PubMed1990

Screening of selected male blood donors for p24 antigen of human immunodeficiency virus type 1. The Transfusion Safety Study Group.

BACKGROUND: The p24 antigen of human immunodeficiency virus type 1 (HIV-1) is sometimes detected before antibody (anti-HIV-1) is detectable in the serum of recently infected persons. This has led to the consideration of p24-antigen testing for routine screening of blood donors. METHODS: To estimate how many HIV-infected seronegative donors would be identified if p24-antigen screening was introduced, we tested selected donations from a repository of 200,000 serum samples from voluntary donors that was established in late 1984 and early 1985. The 8597 serum samples selected for p24-antigen screening were chosen because their donors had demographic characteristics known to be associated with a high prevalence of seropositivity. RESULTS: The prevalence of anti-HIV-1 antibodies in the 1984-1985 serum samples selected for p24-antigen screening was 1.54 percent--more than 100 times the 0.012 percent prevalence in present-day donations in the United States. The antigen was detected in 15 of 132 serum samples (11.4 percent) from donors who had already been confirmed as seropositive. No instance of confirmed positivity for p24 antigen was found among the 8465 seronegative serum samples. CONCLUSIONS: These data indicate that the yield of screening for p24 antigen in volunteer donors to identify HIV-1 carriers would be negligible. We therefore recommend against routine screening with currently available p24-antigen assays.

Blood Donors↗
PubMed1990

Association between vaginal douching and acute pelvic inflammatory disease.

The vaginal douching habits of 100 consecutive municipal hospital patients with verified pelvic inflammatory disease (cases) were compared with those of 762 randomly selected controls (random controls) and 119 women thought to have pelvic inflammatory disease but in whom the diagnosis was not confirmed by laparoscopy and/or endometrial biopsy specimen (internal controls). Because patients had been symptomatic for no more than 3 weeks, current douching was arbitrarily defined as any douching during the previous 2 months. Current douching was more common among those with pelvic inflammatory disease than among random controls or internal controls. Among current douchers, pelvic inflammatory disease was significantly related to frequency of douching. For example, when cases were compared with random controls, those who douched three or more times per month were 3.6 times more likely than those who douched less than once per month to have confirmed pelvic inflammatory disease. A logistic regression model was used to adjust for demographic, behavioral, and other possible confounding variables. Even after adjustments, douching during the previous 2 months remained associated with pelvic inflammatory disease. These data suggest that among these women vaginal douching may be a risk factor for pelvic inflammatory disease.

Acute Disease↗
PubMed1990

Decreased risk of symptomatic chlamydial pelvic inflammatory disease associated with oral contraceptive use.

Studies have shown that oral contraceptive use may protect against pelvic inflammatory disease (PID), but it is not known whether oral contraceptives protect against the disease among women already infected with Chlamydia trachomatis or Neisseria gonorrhoeae. The relationship between oral contraceptive use and PID was analyzed in a case-control study of 141 women with verified PID and 739 randomly selected, sexually active women with no clinical evidence of the disease. Case and control subjects were stratified on the basis of infection with C trachomatis, N gonorrhoeae, or neither organism. Among women infected with C trachomatis alone, those with PID were less likely than control subjects to use oral contraceptives. The association was significant when oral contraceptive use was compared with nonuse (odds ratio, 0.22; 95% confidence interval, 0.08 to 0.64) and with noncontraception (odds ratio, 0.17; 95% confidence interval, 0.06 to 0.53) and remained so after adjusting for potential confounding variables by logistic regression analysis. Among women infected with N gonorrhoeae alone, no association was found between use of oral contraceptives and PID. These data suggest that oral contraceptive use protects against symptomatic PID among women infected with C trachomatis but not among those infected with N gonorrhoeae.

Adolescent↗
PubMed1990

Epidemiology of hepatitis C virus. A preliminary study in volunteer blood donors.

In a survey carried out from 1985 through 1986, volunteer blood donors to The Greater New York Blood Program were tested for two surrogate markers for non-A, non-B hepatitis--elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen. Stored serum samples from selected donors were also recently tested for antibody to hepatitis C virus (anti-HCV). Anti-HCV was detected in 0.9% to 1.4% of donors and was higher in black and Hispanic donors than in white donors. Anti-HCV prevalence increased with increasing age through the fourth decade of life, but decreased thereafter, possibly reflecting the disappearance of detectable antibody with time. Anti-HCV correlated with both alanine aminotransferase level and the presence or absence of antibody to hepatitis B core antigen. These associations suggest that donor screening for elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen was, as expected, at least partially effective in preventing transfusion-associated non-A, non-B hepatitis. The detection of anti-HCV in donors who have neither an elevation of alanine aminotransferase level nor presence of antibody to hepatitis B core antigen suggests that donor screening for anti-HCV will further reduce the risk of transfusion-associated hepatitis.

Adult↗
PubMed1990

Non-A, non-B hepatitis and antibody to hepatitis C virus.

Stored serum samples from the Transfusion-transmitted Viruses Study in the 1970s were tested for the presence of antibody to hepatitis C virus (anti-HCV). Single specimens from five control subjects who did not receive transfusions tested negative for anti-HCV. Of four control subjects who did not receive transfusions and who developed non-A, non-B (NANB) hepatitis after hospitalization, three remained anti-HCV negative; the fourth person with postoperative NANB hepatitis tested anti-HCV positive before the operation. Five transfusion recipients with posttransfusion hepatitis B virus infection remained seronegative; a sixth with NANB hepatitis as well as hepatitis B virus infection had seroconversion for anti-HCV. Five of nine transfusion recipients with NANB hepatitis had anti-HCV seroconversion. These results show that present anti-HCV testing demonstrates an etiologic basis for approximately half of the cases of transfusion-associated NANB hepatitis, particularly those that develop chronicity. Although cases of NANB hepatitis without seroconversion may be explained otherwise, they may be caused by another, presently unidentified, virus.

Blood Transfusion↗
PubMed1990

Comparative distribution of marrow CFU-e and CFU-gm progenitors in different anatomic sites in the dog.

The interpretation of marrow cloning activity, particularly in serial cultures, is greatly influenced by the reproducibility of the collected marrow samples. In order to establish whether bone marrow cloning activities and precision of the cloning assays are influenced by the site of bone marrow collection in the dog, we studied the incidence of marrow erythroid (CFU-e) and granulocyte-macrophage (CFU-gm) progenitor cells in the iliac crest, sternum, vertebrae, femur, and humerus, using microplasma clot and soft agar culture systems. Marrow samples obtained from the femur and humerus revealed consistently higher cell concentrations than those from the iliac crest, vertebrae, or sternum. Those aspirated from the sternum and vertebrae had lower cell concentrations and were less reproducible. Statistical analysis revealed no significant differences in the incidence of marrow CFU-e and CFU-gm progenitor cells between the femur, humerus, iliac crest or vertebrae. With multiple sampling, the marrow cloning efficiency was consistent and reproducible within the individual dogs. We conclude that the distribution of CFU-e and CFU-gm is comparable throughout the active marrow in the dog and that these sites may be used interchangeably for multiple quantitative analysis of marrow hematopoietic progenitor cells.

Agar↗
PubMed1990

Search for epitope-specific antibody responses to the human immunodeficiency virus (HIV-1) envelope glycoproteins signifying resistance to disease development.

It is essential for the development of strategies for prevention and therapy of human immunodeficiency virus (HIV-1) infections to define host factors playing a dominant role in determining the clinical outcome of infection. Antibodies directed against restricted regions of the HIV-1 glycoproteins gp120 and gp41 are likely to represent important factors involved in host defense against HIV-1. Definition of qualitative and quantitative differences in the spectrum of anti-gp120 and anti-gp41 antibodies between two vastly different groups of HIV-1-infected individuals, long-term asymptomatic carriers, and individuals with acquired immunodeficiency syndrome (AIDS) who died, might reveal the epitope specificity of antibodies contributing to prevention of clinical disease. To accomplish this goal, sera from both groups were assayed for antibodies recognizing synthetic peptides from gp120/gp41 which were shown in earlier experiments to mimic epitopes on the two HIV-1 glycoproteins. None of the sera recognized all of the distinct 27 peptides from gp120 and gp41. The spectrum of antibodies was distinct for each of the sera from both groups of HIV-1-infected individuals. Nevertheless, antibody responses distinguishing the two groups from each other were discerned. In particular, it was possible to predict the unfavorable outcome of disease by comparative measurements of levels of antibodies to a peptide (303-338), corresponding to the entire V3 hypervariable loop of gp120 and/or by providing evidence for declining levels of these antibodies during the course of infection. Antibodies recognizing additional peptides [(219-245), (280-306), (425-452), (658-682), (729-758), (808-845), and (845-862)] were significantly less prevalent in AIDS patients than in asymptomatic carriers. It appears possible that maintenance of high levels of the respective antibodies would contribute to preventing AIDS in HIV-1-infected individuals. Active immunization with antigens containing epitopes defined by the respective peptides and/or administration of the corresponding antibodies may be considered as a modality for therapy of HIV-1 infections.

Epitopes↗
PubMed1990

Comparison of Southern transfer hybridization and dot filter hybridization for detection of cervical human papillomavirus infection with types 6, 11, 16, 18, 31, 33, and 35.

A commercial dot filter hybridization kit (Virapap Kit) was compared with Southern transfer hybridization for the detection of seven types of human papillomavirus (HPV) in cervical specimens from 450 consecutive females attending a sexually transmitted diseases clinic. In comparison with Southern transfer hybridization, performed with the same probes used in the dot filter kit, the sensitivity, specificity, and positive and negative predictive values of dot filter hybridization were 90%, 94%, 74%, and 98%, respectively. Among patients with cervical cytologic dysplasia, HPV DNA was detected in 44% by dot filter hybridization and in 35% by Southern transfer hybridization. Although 26% of specimens positive by dot filter hybridization were not confirmed by Southern transfer hybridization, cervical dysplasia was detected in 5 (25%) of 20 with HPV DNA detected by dot filter hybridization alone, compared with 25 (8%) of those with no definitive evidence of HPV by either method (P = 0.009) and with 16 (30%) of 53 with HPV DNA detected by both methods (P = 0.7). The kappa statistic for interobserver and intraobserver reproducibility for interpretation of blots was similar for the two methods. The dot filter hybridization method evaluated appears to be a satisfactory alternative to Southern transfer hybridization for detection of HPV DNA.

Adolescent↗
PubMed1989

An assay for circulating antibodies to a major etiologic virus of human non-A, non-B hepatitis.

A specific assay has been developed for a blood-borne non-A, non-B hepatitis (NANBH) virus in which a polypeptide synthesized in recombinant yeast clones of the hepatitis C virus (HCV) is used to capture circulating viral antibodies. HCV antibodies were detected in six of seven human sera that were shown previously to transmit NANBH to chimpanzees. Assays of ten blood transfusions in the United States that resulted in chronic NANBH revealed that there was at least one positive blood donor in nine of these cases and that all ten recipients seroconverted during their illnesses. About 80 percent of chronic, post-transfusion NANBH (PT-NANBH) patients from Italy and Japan had circulating HCV antibody; a much lower frequency (15 percent) was observed in acute, resolving infections. In addition, 58 percent of NANBH patients from the United States with no identifiable source of parenteral exposure to the virus were also positive for HCV antibody. These data indicate that HCV is a major cause of NANBH throughout the world.

Antibodies, Viral↗
PubMed1989

Clinical manifestations of vaginal trichomoniasis.

Trichomonas vaginalis was detected by culture or wet-mount examination in 118 (15%) of 779 randomly selected women attending a sexually transmitted disease clinic. Vaginal trichomoniasis was significantly associated with symptoms of yellow discharge, abnormal vaginal odor, and vulvar itching and with signs of colpitis macularis ("strawberry cervix"), purulent vaginal discharge, and vaginal and vulvar erythema. A logistic regression model was used to adjust for coinfections, as well as for demographic, behavioral, and other possible confounding variables. Trichomonas vaginalis remained significantly associated with symptoms of yellow vaginal discharge (odds ratio [OR] = 2.4) and vulvar itching (OR = 3.0) and with signs of colpitis macularis (OR = 241), purulent vaginal discharge (OR = 8.0), vulvar erythema (OR = 2.5), and vaginal erythema (OR = 4.3). The sensitivity of symptoms and signs associated with trichomoniasis was relatively low. Nevertheless, clinical manifestations can be used to identify those patients for whom a wet-mount examination would likely have high yield. Careful clinical examination and selective use of wet-mount examination together with wider use of more sensitive tests for subclinical infection, such as culture or direct immunofluorescent staining of vaginal fluid, could lead to improved detection and control of this infection.

Adult↗
PubMed1989

Randomized treatment of mucopurulent cervicitis with doxycycline or amoxicillin.

A randomized trial of doxycycline versus amoxicillin was performed to treat mucopurulent cervicitis. Chlamydia trachomatis, the most common single agent associated with mucopurulent cervicitis, was isolated from 30 (47%) and Neisseria gonorrhoeae from five (8%) of 64 patients. Patients were followed up for 3 months, and the effect of treatment was assessed by clinical (presence of endocervical mucopus, cervicitis severity score, and number of polymorphonuclear leukocytes on Gram-stained smears of endocervical secretions) and microbiologic criteria. Doxycycline and amoxicillin were equally effective for treating chlamydial and nonchlamydial cervicitis. However, endocervical mucopus was still present in 18% of the patients in both treatment groups after 2 months and in 23% of the doxycycline group and 33% of the amoxicillin group after 3 months of therapy. The cause of persistent/recurrent mucopus after antimicrobial treatment was not explained by relapse or reinfection with Chlamydia trachomatis, Neisseria gonorrhoeae, genital mycoplasmas, or Gardnerella vaginalis, but persistence was associated with the degree of cervical ectopy.

Amoxicillin↗
PubMed1989

Prevalence of genital papillomavirus infection among women attending a college student health clinic or a sexually transmitted disease clinic.

We examined 454 women randomly selected from a Sexually Transmitted Disease (STD) Clinic and 545 consecutive college women undergoing annual examination. Patients were examined for visible genital warts, koilocytes, and human papillomavirus (HPV) antigen on cervical smears and for cervical HPV DNA types 6, 11, 16, 18, and 31. Genital warts were found in 11% of STD Clinic patients and 2% of students (P less than .001). Among those women without genital warts, HPV DNA or antigen was detected in cervical specimens from 10.6% of STD Clinic patients and 11.4% of students (P = .73), with HPV type 16, 18, or 31 being 9.8 times more frequent than cervical HPV 6 or 11 among students and 5.8 times more frequent among STD Clinic patients. Dysplasia was present in 53% of those with HPV type 6 or 11 and in 41% of those with HPV type 16, 18, or 31 DNA.

Adult↗
PubMed1989

Factors determining the digestive efficiency of the domesticated donkey (Equus asinus asinus).

Factors determining the digestive efficiency of donkeys were studied in animals fed either a low quality roughage (wheat straw: 77.1% neutral detergent fibre, 2.8% crude protein) or a high quality forage (alfalfa hay: 47.5% neutral detergent fibre, 22.7% crude protein). The neutral detergent fibre (NDF) intake when fed wheat straw was 1693 +/- 268 g animal-1 day-1, 10% higher than when fed alfalfa hay. Digestive coefficient of NDF and acid detergent fibre (ADF) when fed wheat straw amounted to 50.9 +/- 4.9 and 42.0 +/- 4.1% respectively. NDF and ADF apparent digestibilities and mean retention times (37.7 +/- 1.7 and 36.4 +/- 3.2 h respectively) were not significantly different (P greater than 0.05) between the two diets. The donkey appears to digest cell wall constituents as efficiently as the Bedouin goat when on low quality roughage, but less efficiently when fed alfalfa hay. Its energy digestibility is, however, as high as that reported for the Bedouin goat. The donkey's high energy digestibility is related to its capacity to digest soluble food components more efficiently than the ruminant. The mean retention time in the donkey is shorter than in the Bedouin goat and is consistent with its capacity to compensate for a lower quality diet by increasing its intake rate. Recycling of urea in donkeys maintained on wheat straw amounted to 75.5 +/- 13.0% of the entry rate. A decrease in the rate of renal urea filtration, coupled with an increase in the fraction reabsorbed, increased the retention of nitrogenous waste and permitted recycling of nitrogen into the gut.

Animal Feed↗
PubMed1988

Diagnosis of trichomoniasis. Comparison of conventional wet-mount examination with cytologic studies, cultures, and monoclonal antibody staining of direct specimens.

The accuracy of (1) conventional wet-mount examination, (2) Papanicolaou-stained gynecologic smears, (3) a direct slide test using fluorescein-conjugated monoclonal antibodies against Trichomonas vaginalis, and (4) two different culture media for the diagnosis of trichomoniasis in a high-risk population of 600 women was compared. Use of Feinberg-Whittington or Diamond's culture medium resulted in a diagnosis of 82 and 78 cases, respectively, and the combination of two cultures identified 88 infected women. In comparison, wet-mount examination detected only 53 (60%) of the cases. Cytologic smears were interpreted as positive for T vaginalis in 49 (56%) of the 88 cases but also resulted in seven false-positive smears, and specimens from 18 women with negative cultures were interpreted as "suspicious" for trichomoniasis. Monoclonal antibody staining detected 76 (86%) of the 88 positive specimens, including 27 (77%) of the 35 cases missed by wet-mount examination. In summary, wet-mount and cytologic studies were insensitive, and cytology study was the least specific method for diagnosis of trichomoniasis. Direct immunofluorescence with monoclonal antibodies holds promise as a sensitive and specific alternative to cultures for rapid detection of T vaginalis in clinical specimens.

Animals↗