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Biomedical subjects

J Jamison

Publications and source records attributed to J Jamison.

10 recordsLinked to original sources
PubMed1999

Use of alcohol fixed cytospins protected by 10% polyethylene glycol in immunocytology external quality assurance.

AIMS: To provide cytospins as a means of external quality assurance (EQA), while maintaining antigen expression integrity and achieving uniformity of material for all participating laboratories. METHODS: Cells were collected from two adenocarcinoma and one reactive pleural effusion specimens. Lymphoid cells were also collected through aspiration of a resected tonsil specimen. All cells were collected in Hanks balanced salt solution (HBSS); cytospins were made and fixed in methanol or acetone alone or protected using a layer of 10% polyethylene glycol (PEG) in 50% methanol. Two laboratories participated (RGHT and UCL). RESULTS: Cytokeratin expression detected using either CAM5.2 or AE1/AE3 antibodies was sensitive to temperature. Without PEG, unacceptable or negative staining was seen within six weeks of preparation. LCA was not sensitive to temperature, with good staining scores being achieved after eight weeks following preparation. CONCLUSIONS: It is possible to send alcohol fixed, air dried cytospins to laboratories participating as part of an EQA scheme for immunocytology. Some antigens will require protection from temperature variations during transit. A layer of 10% PEG in 50% methanol, allowed to air dry, is suitable for this purpose. Participating laboratories will only have to remove this layer using methanol before their localisation technique for assessment.

Adenocarcinoma↗
PubMed1998

Submicrovolt flicker electroretinogram: cycle-by-cycle recording of multiple harmonics with statistical estimation of measurement uncertainty.

PURPOSE: To study cycle-by-cycle recording of small-amplitude flicker-electroretinogram (ERG) responses and analyze results with robust statistical methods to estimate the measurement uncertainty. METHODS: Flicker ERGs at 32 Hz were recorded simultaneously from both eyes of patients with retinal degeneration. The ERG was amplified under wide-band (1-1000 Hz) conditions, digitized at 6144 Hz/eye, and multiplied point for point (192 points/cycle) by sine and cosine functions within each 1/32-second flash cycle to extract coefficients for six harmonic components of a discrete Fourier transform in real time. Amplitude windowing was not used, and all data were saved for subsequent statistical processing to identify and remove large-amplitude artifacts discretely and to search for quiet recording periods that minimized small-amplitude noise. RESULTS: Plots of amplitude and phase indicated far outlying noise points that were excised from the data. The SD of sequential intervals on a time line of the sine component identified quiet periods that minimized small-amplitude noise and improved measurement consistency. The SE of the response mean provided an estimate of measurement uncertainty. CONCLUSIONS: The harmonic components of many individual responses are captured quickly (e.g., 500 responses in 15.6 seconds) for post hoc statistical analysis, using mathematical algorithms that are precisely reproducible to facilitate comparison of results from all laboratories. Graphical time lines of responses allow separation of artifact transients from gaussian noise for elimination of noisy periods without disturbing the stored information. Statistical estimates of measurement uncertainty are determined on-line to allow immediate feedback during the recording session. Amplitude-phase plots of the multiple harmonic components, along with reconstructed analog waveforms, provide results in a readily assimilated manner for comparison of all testing sessions.

Electroretinography↗
PubMed1994

Likelihood ratios for deoxyribonucleic acid (DNA) typing in criminal cases.

The likelihood ratio approach for DNA typing in criminal cases is described. It is shown how this approach uses both the sizes and pattern of discrepancies between the crime scene profile of fragment lengths and the suspect profile for quantifying the strength of the evidence. In contrast to the current match-binning approach, it avoids an initial decision about whether the two profiles match. Likelihood ratios for pairs of profiles that meet the published statistical criteria for a match show a wide range of values including some that indicate the evidence is strongly against identity.

Criminology↗
PubMed1990

In vitro antiviral activity of poly (A-U) and ellipticines.

The role of N2-methyl-9-hydroxy-ellipticine (NMHE) and N2,N6-dimethyl-9-hydroxy-ellipticine (DMHE) in modulating the antiviral activity of poly (A-U) was examined using a human foreskin fibroblast-vesicular stomatitis virus (HSF-VSV) bioassay in which the concentration of poly (A-U) was fixed at 0.05 mM or 0.2 mM while the NMHE or DMHE concentration was varied to produce variable NMHE (or DMHE)/ribonucleotide ratios ranging from 1:16 to 2:1. Poly (A-U), NMHE and DMHE tested individually were not efficacious antiviral agents. When the poly (A-U) was combined with the NMHE or DMHE, the antiviral activity of the poly (A-U) was potentiated 16- to 20-fold a NMHE (or DMHE)/ribonucleotide ratios in the region of 1/4. Poly (A-U), NMHE and DMHE induce beta-IFN. The interferon-inducing activity of the NMHE (or DMHE)/poly (A-U) combination was equal to the sum of the interferon-inducing activity of the poly (A-U) alone and the NMHE (or DMHE) alone. The direct viral inactivation study demonstrated that NMHE, DMHE, poly (A-U) and the NMHE (or DMHE)/poly (A-U) combinations did not inactivate VSV at concentrations near the 50% viral inhibitory dose. Photomicrographs of HSF cells incubated with NMHE alone or with a NMHE/poly (A-U) combination suggest that poly (A-U) affects the subcellular distribution of the NMHE by steering the NMHE to the nucleolus. These observations suggest that modulation of a nuclear process may be responsible for the enhanced antiviral activity.

Alkaloids↗
PubMed1988

Immunoreactive ACTH, beta-endorphin, and cortisol levels in plasma following spinal manipulative therapy.

This study examines the possibility of a humorally mediated analgesic response to spinal manipulative therapy by determination of plasma levels of beta-endorphin, adrenocorticotropic hormone (ACTH), and cortisol before and after intervention. Forty male subjects (20 symptomatic, 20 asymptomatic) were allocated into four equal groups. Two treatment groups were given spinal manipulative therapy, and two groups underwent a sham procedure. Blood samples were taken via indwelling butterfly needles pre- and postintervention in all four groups, and levels of immunoreactive ACTH, immunoreactive beta-endorphin, and cortisol determined by radioimmunoassay. No differences in ACTH or beta-endorphin were found between sham and treated groups, or between pre- and postintervention in any group; cortisol levels fell over the course of the study in all groups. The findings thus appear to exclude a humoral role for beta-endorphin in mediating the analgesic response to spinal manipulative therapy; in addition, they suggest that such therapy is not a stressor that activates the hypothalamo-pituitary-adrenal axis.

Adolescent↗
PubMedDate not supplied

Racial variation in vaginal pH among healthy sexually active adolescents.

BACKGROUND AND OBJECTIVES: To determine if there are racial differences in vaginal pH that could account for the increased prevalence of trichomoniasis among sexually active black women. STUDY DESIGN: We measured the pH of vaginal secretions in a group of 273 sexually active, adolescent females without evidence of lower genital tract infection or cervical inflammation. RESULTS: Univariate analyses revealed that seven factors (black race, current alcohol use, nonsmoking status, gravidity, parity, and younger chronologic and gynecologic age) were significantly associated with a more alkaline vaginal pH. After a step-wise multiple regression analysis only three factors (black race, current alcohol use and parity) remained significantly related to vaginal pH, with the strongest association for black race (mean + standard deviation [SD] for vaginal pH among black adolescents 5.3 + 0.7 compared to 4.7 + 0.6 for other adolescents; P < .0001). CONCLUSION: The pathophysiologic mechanisms that underlie the racial differences we identified in vaginal pH remain to be elucidated. Nevertheless, we speculate that race-related variations in the pH of normal vaginal secretions may decrease the resistance of black adolescents, one of the highest-risk obstetric population in this country, to common vaginal infections, such as trichomoniasis and bacterial vaginosis.

Adolescent↗
PubMedDate not supplied

Femoral version and neck shaft angle.

We measured femoral anteversion by the Kingsley-Olmsted method in 24 unpaired, dry femurs. When the head and neck of the same femurs were measured by computed tomography (CT) scan, measurement was 5 degrees less than the Kingsley-Olmsted method, whereas ultrasound of the head and neck was 5 degrees higher. An anterior flat plane was also defined to help measure anteversion in patients with a high neck shaft angle. Physical and ultrasound measurement correlated well with the previous measurement by the Kingsley-Olmsted method and CT scan of anteversion. Although measurement by CT scan and ultrasound are different their results are both reproducible and measure the same parameters; however, ultrasound measurement yields a number approximately 10 degrees higher.

Anthropometry↗