Biomedical subjects

Amjad Horani

Publications and source records attributed to Amjad Horani.

7 recordsLinked to original sources

PubMed2006

Beneficial effect of glatiramer acetate (Copaxone) on immune modulation of experimental hepatic fibrosis.

While CD8 subsets activate hepatic fibrosis, natural killer (NK) cells exhibit antifibrotic activity. Glatiramer acetate (GA) is an immune modulator for multiple sclerosis. We assessed the potential impact of GA on mouse hepatic fibrogenesis. Hepatic fibrosis was induced in C57BL/6 mice by intraperitoneal administration of carbon tetrachloride (CCl(4)) for 6 wk. During the last 2 wk, animals were also treated with either GA (200 mu/day ip) or medium and compared with naive and fibrotic mice (8 animals/group). GA markedly attenuated fibrosis without altering reactive oxygen species production. By morphometric measurement of Sirius red-stained tissue sections, the relative fibrosis area decreased from 5.28 +/- 0.32% (mean +/- SE) in the untreated CCl(4) group to 2.01 +/- 0.28% in CCl(4)+GA-treated animals, compared with 0.38 +/- 0.07% in naive mice. alpha-Smooth muscle actin immunoblotting and mRNA expression revealed a similar pattern. Serum aminotransferase and Ishak-Knodell necroinflammatory score were markedly elevated, to the same extent, in both CCl(4)-treated groups. Fibrosis induction was associated with significant increase in CD8 subsets and decrease in CD4 T cells. After GA treatment, however, NK content, CD4(+)CD25(+)FoxP3(+) cells, hepatic expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and apoptosis of hepatic stellate cells were all increased. Serum interleukin (IL)-10 levels markedly rose, whereas IL-4 fell. In vitro activation of human hepatic stellate cells cocultured with hepatitis C virus-derived peripheral blood lymphocytes decreased when lymphocytes were preincubated with GA before coculture. In an animal model of hepatic fibrosis, GA has an antifibrotic effect associated with decreased CD8 cells and reduced serum IL-4 levels and increased NK cells, CD4(+)CD25(+)FoxP3(+) cells, TRAIL, and elevated serum IL-10 levels.

Actins↗

PubMed2006

Anti-fibrotic activity of NK cells in experimental liver injury through killing of activated HSC.

BACKGROUND/AIMS: We have investigated the role of natural killer (NK) cells in hepatic fibrogenesis. Mouse NK cells express both inhibitory/activating-killing-immunoglobulin-related-receptors (iKIR/aKIR) specific for Class-I-molecules. METHODS: Hepatic fibrosis induced by carbon-tetrachloride (CCl4) was compared between wild-type (WT) male-BALBc; combined-immunodeficiency (SCID, lacking B/T-cells); and SCID-BEIGE-mice (lacking B/T/NK cells), and naive mice. RESULTS: Hepatic fibrosis significantly increased in all CCl4-treated groups. SCID-BEIGE mice had more fibrosis than SCID-mice (P<0.0001) as assessed by morphometry of sirius-red stained tissue sections. Following fibrosis, hepatic NK cells significantly decreased, the aKIR:iKIR-ratio significantly increased while Class-I expression on HSC decreased (P<0.001). Both freshly isolated and in situ HSC displayed a significant increase in cellular apoptosis following fibrosis induction. Confocal microscopy demonstrated the direct adhesion of NK cells to HSC in mouse liver sections and in vitro human NK/HSC co-culture. In human HSC there was decreased Class-I expression and increased apoptosis as well, which was further increased following blocking of either HSC-related Class-I or NK-related killer inhibitory receptors. Apoptosis was inhibited by pre-incubation of NK cells with the granzyme inhibitor 3,4-dichloroisocoumarin. CONCLUSIONS: During liver injury, NK cells have an anti-fibrotic activity at least in part through stimulation of HSC killing.

Actins↗

PubMed2005

Operator learning effect and interoperator reproducibility of the scanning laser polarimeter with variable corneal compensation.

PURPOSE: To ascertain operator learning effect, and to quantify the interoperator reproducibility, using the newly introduced GDx VCC (variable corneal compensator) scanning laser polarimeter. DESIGN: Prospective instrument validation study. PARTICIPANTS: Three operators with no prior experience in operating the GDx VCC examined one randomly chosen eye of each of 30 randomly ordered subjects (15 glaucoma patients and 15 normal subjects). METHODS: Each study eye was scanned by the 3 operators in a random sequence during a single session. Five GDx parameters were analyzed: TSNIT (temporal, superior, nasal, inferior, temporal) Average, TSNIT Standard Deviation (SD), Superior Average, Inferior Average, and Nerve Fiber Indicator (NFI). MAIN OUTCOME MEASURES: Retinal nerve fiber layer (RNFL) thickness GDx parameters across operators. RESULTS: A learning effect was not found for any of the operators for any of the 5 GDx parameters studied. Reproducibility for each GDx parameter was measured as the mean SD value of the measurements taken by the 3 operators. Interoperator reproducibilities for normal and glaucomatous eyes, respectively, were 0.8 and 1.6 microm (TSNIT Average), 1.7 and 2.2 microm (Superior Average), 1.6 and 2.7 microm (Inferior Average), 1.3 and 1.7 microm (TSNIT SD), and 1.4 and 4.6 microm (NFI). The data obtained by each operator were highly correlated with those of the other 2 operators. CONCLUSIONS: With the commercially available GDx VCC, a learning effect was not found for 3 novice operators. In addition, RNFL measurements seem highly reproducible across operators.

Adult↗

PubMed2004

The reliability of frequency-doubling perimetry in young children.

OBJECTIVE: To evaluate whether healthy young children are able to perform automated static perimetry reliably using the frequency-doubling technology (FDT) perimeter. DESIGN: Prospective, observational case series. PARTICIPANTS: Forty healthy children aged 4 to 14 years. TESTING: Subjects underwent, in 1 randomly chosen eye, 2 consecutive visual field (VF) tests using the C-20 full-threshold program of the commercially available FDT. MAIN OUTCOME MEASURES: Global measures included mean deviation (MD), pattern standard deviation (PSD), test duration and reliability indices, including fixation losses and false-positive and false-negative errors. Fixation losses are checked 6 times throughout the examination, rather than being continuously monitored. Two scoring systems, based on the total deviation probability plot, classified each VF as normal or abnormal. RESULTS: All subjects completed the VF test. The better of 2 examinations (as determined by the MD score) was used for analysis. The average test duration was 4.9+/-0.7 minutes for the entire group. The mean MD and PSD were -0.78+/-4.9 and 6.7+/-6.2, respectively. A clear correlation to age was found for MD, PSD, abnormality of the VF, and test duration (all P<0.05). Of all VFs, 32.5% were unreliable, such that at younger than 8 years of age, 42.9% of the VFs were unreliable, compared with 23.1% for those older than 8 years. Younger than 8 years of age, 78.6% of VFs were abnormal, whereas for ages 8 years and older, 26.9% of VFs were abnormal. CONCLUSIONS: Frequency-doubling technology seems to be a clinically feasible VF method for evaluating young children older than approximately 8 years of age. The reliability indices, MD, test duration, and the reproducibility of the VF test were found to be highly correlated with age, in such a way that these parameters all improved with increasing age.

Adolescent↗

PubMed2002

The learning effect in visual field testing of healthy subjects using frequency doubling technology.

PURPOSE: To evaluate the presence, duration and magnitude of a learning effect in serial visual field (VF) testing, using the commercially available frequency doubling technology (FDT) instrument. PATIENTS AND METHODS: 21 healthy adults with no prior VF experience underwent 6 serial VF tests, using the full-threshold C-20 program of the Zeiss-Humphrey FDT analyzer, on one randomly chosen eye. Tests were spaced at least two days apart. RESULTS: The average mean sensitivity was 32.37 +/- 2.6 dB; the average mean deviation (MD) was 1.22 +/- 1.8 dB. The MD at the first examination (0.28 +/- 2.1 dB) was significantly poorer than at any of the other testing sessions (p<0.003). Similarly, the mean sensitivity at the first examination (31.16 +/- 3.0 dB) was significantly lower than any other testing session (p<0.004). The proportion of improvement from the first to the second session was 63% and 65% of the total improvement, for mean sensitivity and MD, respectively. Mean test duration showed a modest reduction, from 4.40 +/- 0.3 minutes in the first session to 4.17 +/- 0.4 minutes in the last session (p = 0.023). A sub-analysis comparison of the different VF segments showed a more prominent learning effect in the peripheral and nasal visual segments (p<0.0001). CONCLUSION: Baseline measurements should best rely on the second testing session, since MD and mean sensitivity are somewhat poorer when subjects with no prior VF experience are first tested on the FDT instrument. This may be especially true for the purpose of following patients over time.

Adult↗

PubMedDate not supplied

The effect of pupil dilation on scanning laser polarimetry with variable corneal compensation.

BACKGROUND AND OBJECTIVE: The feasibility and reproducibility of scanning laser polarimetry performed through dilated pupils rather than through non-dilated pupils was tested. PATIENTS AND METHODS: One eye each of 36 subjects (12 normal, 12 suspected glaucoma, and 12 glaucoma) was scanned using a single GDx unit with variable corneal compensator (GDx-VCC; Laser Diagnostic Technologies, Inc., San Diego, CA). Two scans prior to and two scans after dilation were performed on each study eye, resetting the cornea compensation prior to each scan. The dilated eye was viewed off-center, such that the whitish focusing patch was projected on the 9-o'clock peripheral iris. After adequate anteroposterior focus, the pupil was centered and a scan was acquired. Each of 5 GDx parameters was evaluated comparing the pre-dilation and post-dilation scans. RESULTS: No statistically significant difference was found between pre-dilation and post-dilation measurements. There was a high pre-dilation to post-dilation correlation of 98%, 98%, 98%, 93%, and 95% for nerve fiber indicator, TSNIT average, TSNIT standard deviation, superior average, and inferior average, respectively. Less than 5% of the measurement variability was attributed to changes in pupil size (R2 ranging from 0.024 to 0.047). Stratifying the data by diagnostic groups yielded similar results. CONCLUSIONS: Pharmacologic mydriasis was not found to influence the retinal nerve fiber layer measurements acquired using the GDx-VCC. Results were comparable to scans achieved in the same eyes prior to dilation.

Aged↗

PubMedDate not supplied

Correlating structure with function in end-stage glaucoma.

BACKGROUND AND OBJECTIVE: To correlate structure and function in eyes with end-stage glaucoma. PATIENTS AND METHODS: Fifty-six eyes of 48 patients with glaucoma presenting with end-stage glaucoma underwent scanning laser polarimetry (SLP) imaging using a commercially available GDx-variable corneal compensator unit (GDx-VCC; Laser Diagnostics Technologies, Inc., San Diego, CA). End-stage glaucoma was defined by both disc appearance and standard automated perimetry visual field criteria. Standard automated perimetry parameters included: mean deviation, pattern standard deviation, and total deviation plot. GDx parameters included: TSNIT average, superior average, inferior average, TSNIT standard deviation, and nerve fiber indicator. RESULTS: The visual field mean deviation was -26.75 +/- 3.50 dB. The remaining retinal nerve fiber layer measured in this group of eyes was: TSNIT average, 29.76 +/- 5.81 microm; superior average, 30.76 +/- 6.25 microm; and inferior average, 31.14 +/- 7.20 microm. A low structure-function correlation was found when analyzing separately the superior and inferior hemifields (R2 = 0.00001, R2 = 0.0016, respectively). CONCLUSIONS: In eyes with end-stage glaucoma, very thin but existing retinal nerve fiber layer is found on SLP. Such values rarely dropped below 10 to 20 microm. A flattening of the GDx TSNIT pattern was seen, and the correlation between structure and function was not evident.

Adult↗