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Biomedical subjects

M B Brown

Publications and source records attributed to M B Brown.

174 records · Page 10Linked to original sources
PubMedDate not supplied

Circadian immune measures in healthy volunteers: relationship to hypothalamic-pituitary-adrenal axis hormones and sympathetic neurotransmitters.

OBJECTIVE: The purpose of this study is to examine the circadian pattern of specific immunologic measures and to compare observed circadian rhythms of these measures with the well-established circadian rhythms of hypothalamic-pituitary-adrenal axis hormones and sympathetic neurotransmitters. METHODS: Blood samples were collected every 2 hours for a total of 24 hours from nine healthy volunteers. The blood samples were assayed for hormones and immune measures, including adrenocorticotropic hormone (ACTH), cortisol, norepinephrine, and epinephrine. The immune measures included percentage and absolute number of neutrophils, lymphocytes, the lymphocyte subsets CD3+ (T cells), CD4+ (T helper/inducer), CD8+ (T suppressor/cytotoxic), CD56+ (natural killer [NK] cells) and NK cell activity (NKCA). RESULTS: The following immune measures exhibited a significant circadian rhythm: the percentages of neutrophils, CD4+ cells, and CD56+ cells; the absolute numbers of total lymphocytes, CD3+ cells, CD4+ cells, and CD8+ cells; and NKCA. Cross-correlations between the circadian rhythms of selected hormones and immune measures indicated a strong inverse association between the circadian rhythms of cortisol and the different T cell subsets on the one hand, and a strong direct association between the rhythms of cortisol and the percentage of CD56+ and NKCA on the other. Cross-correlations involving the circadian rhythms of norepinephrine and the same immune measures were in general much weaker and statistically nonsignificant. CONCLUSION: In healthy individuals, both enumerative and functional immune measures exhibit circadian rhythms that seem to be associated most closely with the circadian rhythm of cortisol.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Understanding young children's health beliefs and diabetes regimen adherence.

Previous studies of chronic illness management in children have focused mainly on parents' health beliefs. However, children's health beliefs also can be an important factor in predicting adherence. Indeed, children 6 to 10 years old spend most waking hours away from home, are under less parental supervision, and are becoming more responsible for their own care. The purpose of this study was to develop a pictorial, multi-item instrument to measure dimensions of the Health Belief Model (HBM) and self-efficacy (SE), designed specifically for children with diabetes, thus making it possible to examine both the parent's and child's health beliefs; to explore the relationship between their beliefs; and to examine the extent to which these beliefs are predictors of adherence and metabolic control.

Attitude to Health↗
PubMedDate not supplied

Mycoplasma gallisepticum as a model to assess efficacy of inhalant therapy in budgerigars (Melopsittacus undulatus).

One hundred budgerigars (Melopsittacus undulatus) were infected in the nares (0.02 ml/naris), eye (0.02 ml/eye), and throat (0.2 ml) with Mycoplasma gallisepticum (MG) R strain (3.175 x 10(7) colony-forming units/ml). Fifty birds were treated with sterile broth and served as the controls; 25 of those were exposed to an inhalant, and the others were not treated. Infected birds were divided into four groups; 1) no treatment, 2) penicillin in drinking water, 3) inhalant, 4) both penicillin and inhalant. At days 3, 7, 10, 14, and 21 postinfection (PI), birds were assessed for clinical signs of disease. Five birds in each group were euthanatized at each interval PI; quantitative cultures were performed on lavages from the nares and trachea and on throat swabs; tracheas and air sacs were examined histopathologically. No clinical signs, lesions, or cultural isolations occurred in any control birds. All infected birds developed clinical signs and lesions of the trachea and air sac, but none died. The most severe clinical signs were seen in birds that were infected with MG and received no other intervention or birds that received penicillin in conjunction with infection. Increased respiratory tract lesions were associated with penicillin treatment; aerosol therapy resulted in fewer lesions.

Administration, Inhalation↗
PubMedDate not supplied

Incidence of genital mycoplasmas in women at the time of diagnostic laparoscopy.

The cervicovaginal and endometrial isolation rates of Ureaplasma urealyticum and Mycoplasma hominis and relevant demographic data were obtained at the time of laparoscopy in 193 women from infertile marriage. For comparative purposes, fertile women undergoing laparoscopy for tubal ligation (n = 56) or other purposes (n = 64) were also cultured. Blacks were more likely than caucasians to be infected with either organism in all population types (p less than or equal to .05); however, no differences were noted in cervicovaginal carriage rates for blacks in different patient populations. M. hominis was isolated more frequently from tubal reanastomosis patients and less often from infertile patients, p less than or equal to .001. No differences were noted among the infertile subpopulations. Although the isolation rate of U. urealyticum from the different patient populations was similar, one subpopulation within the infertile population (male factor) was identified in which the prevalence of ureaplasmal infection of the female's lower genital tract was over twice as high (p less than or equal to .005) as in other infertile women. Yet there were no statistically significant differences in the demographic data of this subpopulation as compared to the population of infertile women as a whole. No other clinical subpopulation with single or multiple diagnoses not including male factor had an increased prevalence of infection. Eighty percent of infected, infertile couples had no clinical evidence of male factor infertility, indicating that only certain individuals are affected. This possibly explains why previous studies involving small numbers of patients without regard to clinical subpopulations have failed to show significant differences between infected and uninfected couples.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Antigens of Mycoplasma hominis.

The antigens of Mycoplasma hominis have previously been defined by means of functional assays with rabbit antisera and have been found to be predominantly protein. In this study, sera from humans as well as those from rabbits were shown to recognize protein antigens of M. hominis in an enzyme-linked immunosorbent assay (ELISA) that depended on antigen-binding capacity rather than biologic function. Although the ELISA was more independent of the strain of M. hominis used as antigen than was the mycoplasmacidal test, the use of no single strain allowed detection of more than 87% of positive sera; this observation suggests strain heterogeneity. In contrast to the results of other studies, common surface antigens among the strains of M. hominis used were demonstrated by immunoblot analysis of intact colonies.

Animals↗
PubMedDate not supplied

Isolation of Mycoplasma hominis and Ureaplasma urealyticum from amniotic fluid at 16-20 weeks of gestation: potential effect on outcome of pregnancy.

Samples from 61 amniotic fluids (33 discolored and 28 clear) collected by amniocentesis between 16 and 20 weeks gestation were cultured for microorganisms. Two of the discolored fluids were positive for Mycoplasma hominis, and two were positive for Ureaplasma urealyticum. Neither organism was isolated from samples of clear amniotic fluids. No other bacteria, viruses, or chlamydiae were isolated from fluids of any patient. The results prove that both M. hominis and U. urealyticum can infect the amnionic sac early in gestation without rupture of the fetal membranes. U. urealyticum was shown to cause a clinically silent, chronic (up to two months) intrauterine infection characterized by an intense inflammatory response. Complications in three of the four patients from whom mycoplasmas were isolated suggest, but do not prove, that mycoplasmal infection of amniotic fluid may have an adverse effect on outcome of pregnancy. Further studies are necessary to substantiate this implication and to determine the relationship between infection and discoloration of amniotic fluid.

Adult↗
PubMedDate not supplied

Carotenoids and menstrual cycle phase in young women.

An association between serum carotenoid concentrations and risk for certain cancers has been observed in epidemiological studies. Determinants of serum carotenoid concentrations are known to include dietary intake, plasma lipid concentrations, and body mass. Menstrual cycle phase, which has not been adequately addressed in previous studies, has been suggested to be a possible additional factor to consider in the interpretation of these values in women. We evaluated hormonal status, serum carotenoids, cholesterol, and triglycerides in 48 healthy women at early follicular, mid-luteal, and late luteal phases of one menstrual cycle. Eating patterns were assessed with diet records at two 3-day intervals during the cycle. Analysis was focused on the 30 subjects who were determined to have ovulated during the menstrual cycle under observation. Serum cholesterol was significantly decreased (P < 0.05) in the late luteal phase of an ovulatory cycle. Lutein concentration was increased in the early follicular phase (P < 0.05) and alpha-carotene was increased in the mid-luteal phase (P < 0.05) only if uncorrected for total cholesterol. Other carotenoids did not vary across the menstrual cycle, whether corrected or uncorrected for total cholesterol concentration. In normal healthy ovulating women, serum carotenoids do not appear to vary with menstrual cycle phase when corrected for serum cholesterol concentrations.

Adult↗
PubMedDate not supplied

Variations in prothrombin time and international normalized ratio over 24 hours in warfarin-treated patients.

STUDY OBJECTIVE: To determine the variation of prothrombin times and international normalized ratio (INR) over 24 hours in humans. DESIGN: Prospective, parallel study. SETTING: University-affiliated general clinical research center. PATIENTS: Six patients receiving long-term warfarin therapy and six sex-matched controls. INTERVENTIONS: Warfarin was administered to the patients at 6:00 P.M. MEASUREMENTS AND MAIN RESULTS: Prothrombin times and INR were determined every 2 hours over 24 hours. Time of study entry, meals, and sleep cycles were controlled. A significant cosinor rhythm for prothrombin times and INR (p < or = 0.03) occurred in warfarin-treated patients, suggesting that diurnal variation occurs. The mean difference between the peak and trough prothrombin times was 1.8 +/- 0.9 seconds (range 0.8-3 sec) with a mean change of 9.3% +/- 3.7%. The peak prothrombin time and INR values occurred between 4:00 A.M. and 8:00 A.M. in five patients, and trough values between 6:00 P.M. and midnight in five. No significant cosinor rhythm was noted for controls (p > 0.5). CONCLUSION: Significant variations in prothrombin time and INR occurred in patients receiving warfarin therapy, with the highest values occurring in the morning and the lowest in the evening. These results may have clinical implications for patients receiving either high- or low-intensity warfarin therapy.

Adult↗
PubMedDate not supplied

Comparison of enzyme-linked immunosorbent assay and hemagglutination-inhibition for detection of antibody to Mycoplasma gallisepticum in commercial broiler, fair and exhibition, and experimentally infected birds.

Hemagglutination-inhibition (HI) assay and a new affinity-purified enzyme-linked immunosorbent assay (ELISA) for detection of antibody to Mycoplasma gallisepticum (MG) compared for use as confirmatory tests for the National Poultry Improvement Plan program. Samples from three different poultry populations with different prevalences of MG infection were studied: commercial broiler breeder birds (low prevalence of infection), fair and exhibition birds (moderate prevalence of infection), and experimentally infected birds (high prevalence of infection). Western immunoblots were used to confirm infection status in samples that had discrepancies between HI and ELISA results. The prevalence of infection in commercial broiler birds and in exhibition and fair birds in Florida was determined. Samples from culture-positive Mycoplasma synoviae (MS) flocks also were tested and compared for potential cross-reactions. The prevalence of MG infection was very low (< 1%) in the commercial population, with no significant difference between the HI and ELISA test results (P = 0.3157). The prevalence of MG infection in the fair and exhibition birds tested was approximately 40%, and ELISA was more accurate than HI for confirmation of MG infection in this population (P = 0.036). In birds experimentally infected with MG, there was no significant difference between HI and ELISA results (P = 0.6542). Of the 195 sera collected from flocks confirmed positive for MS by culture, 15% cross-reacted with the MG serum plate agglutination (SPA) test. There were no cross-reactions observed with either the MG ELISA or HI. There was a positive correlation of HI titers to ELISA values (R = 0.621, P < 0.01). Results from this study showed there were no differences between ELISA and HI as confirmatory tests in populations with a low prevalence of MG infection. However, ELISA was superior to HI in a population with moderate levels of MG infection.

Animals↗
PubMedDate not supplied

Evaluation of diagnostic procedures to detect Mycoplasma synoviae in commercial multiplier-breeder farms and commercial hatcheries in Florida.

Sera from 5325 chickens representing 71 commercial poultry flocks were tested for Mycoplasma synoviae (MS) using standard National Poultry Improvement Program (NPIP) testing guidelines. Based on the NPIP guidelines, only sera (N = 195) from flocks that test positive by specific plate agglutination (SPA) were submitted for additional confirmatory tests. Flocks from three multihouse farms were identified as seropositive for MS and confirmed by culture and polymerase chain reaction (PCR). Serum samples (N = 195) from these seropositive flocks were compared by SPA, enzyme-linked immunoassay (ELISA), and hemagglutination-inhibition (HI). Of the 195 sera tested for MS from these flocks, 145 (74%) sera were positive by SPA. Of the 145 SPA-positive sera, the HI test was positive for 127 samples (90.2%), whereas the ELISA was positive for 141 samples (98.6%). This difference between the two tests was significant (P = 0.0006). Significant differences (P = 0.0002) in titer were obtained from paired serum samples that were submitted to three different laboratories for HI analysis. Both the SPA and HI tests failed to detect early infection in newly introduced flocks following depopulation of MS-positive facilities. Both ELISA and PCR detected new infections on these farms. In the MS outbreak described in this study, SPA was not adequate as the sole screening test and HI was not adequate for confirmation of flock infection status. Continued reliance on the same or a similar type of testing could result in missed infections. Confirmation of infection by PCR was preferable to HI and also may be used in place of culture. The findings of this study suggest that ELISA should be considered as a serologic screen in lieu of SPA, screening with SPA may miss MS-infected flocks, and PCR should be considered as a confirmatory test.

Agglutination Tests↗