Search PubMed⌕ Search

Biomedical subjects

C Rogers

Publications and source records attributed to C Rogers.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Histopathological and radioautographical studies on the forestomach of F344 rats treated with butylated hydroxyanisole and related chemicals.

Butylated hydroxyanisole, when fed to male Fischer 344 rats for periods of 9 days or more, led to forestomach epithelial cell necrosis and regeneration. Both the induced proliferation and the histopathological changes were considerably more prevalent in the prefundic region of the forestomach than in the mid-region. Using [Me-3H]thymidine, a specific DNA precursor, and radioautography it was shown that the effect of the antioxidant was apparently threshold at 0.25% in the diet after both 9 days and 3 months of treatment and that the proliferation was dependent on the continuous presence of the antioxidant in the diet at 3 and 6 months. Some other phenols and acids were investigated after 9-27 days' feeding; most induced some degree of epithelial cell proliferation in the rat forestomach, although some had a greater effect on the mid-region than on the prefundic region. These observations are discussed in terms of the likely relevance of butylated hydroxyanisole-induced forestomach tumours to the possibility that the antioxidant may lead to cancer in humans exposed to lower levels in their diet.

Administration, Oral↗
PubMedDate not supplied

Cat sleep: a unique first night effect.

Longitudinal sleep studies in chronically implanted cats revealed a unique first night effect. Unlike other species, during the first 24 hr of sleep recording, the electroencephalogram and reticular formation multiple unit activity revealed more rapid eye movement sleep occurred than during subsequent 24 hr recording sessions. In addition, higher rapid eye movement to slow wave sleep ratios were observed for the first 24 hr as compared to the following days. An increase in wakefulness and decrease in slow wave sleep occurred on the third recording day as compared to the initial 24 hr period. These data have important implications for studies of variables on the sleep pattern of animals.

Animals↗
PubMedDate not supplied

Multiple excimer laser retreatments for scarring and myopic regression following photorefractive keratectomy.

Excimer laser retreatment for scarring with myopic regression following photorefractive keratectomy (PRK) has been reported. We present the 38 month course of a patient who had PRK followed by two retreatments. The patient experienced scarring with myopic regression after an initial PRK with a 5.00 mm ablation zone. These complications recurred 13 months after retreatment with a 5.00 mm ablation zone. Refractive effect, computer-assisted videokeratography measurements, and corneal clarity remained stable 12 months after a second retreatment with a 6.00 mm ablation zone, indicating that retreatment with a larger ablation zone diameter appeared to be an appropriate method for handling this complication.

Cicatrix↗
PubMedDate not supplied

Fatal flecainide intoxication.

Two fatalities resulting from suicidal ingestion of flecainide are described. The decedents, ages 33 and 15, were otherwise healthy; both took their mothers' medications. In one case, from electrocardiographic data, there was found a high-grade conduction block with idioventricular rhythm. Blood and tissue samples from autopsy were analyzed for flecainide by gas chromatography/nitrogen-phosphorous detection and gas chromatography/mass spectrometry. Blood concentrations of 93.7 and 100 mg/L flecainide were found.

Adolescent↗
PubMedDate not supplied

Effect of dexamethasone on conditioned enhancement of natural killer cell activity.

It is believed that the expression of the conditioned natural killer cell activity is regulated through the hypothalamus-pituitary axis. Since the conditioned expression of both the plasma level of adrenocorticotropic hormone and natural killer (NK) cell activity show a sequential rise after exposure to the conditioned stimulus, it was of interest to determine if treatment with dexamethasone could inhibit this response. These studies suggest that treatment with dexamethasone was able to block the expression of the conditioned NK cell activity but was unable to interfere with the pairing of the conditioned stimulus with the unconditioned stimulus. We conclude that the hypothalamic pituitary axis is an integral part of the pathway for stimulation of NK cell activity in the spleen.

Animals↗
PubMedDate not supplied

The direction of the conditioned natural killer cell response can be re-directed with indomethacin and/or handling.

We have used the pairing of camphor odor conditioned stimulus (CS) and injection of poly I:C unconditioned stimulus (US) in a short 3 day single trial conditioning paradigm. Conditioning was done by exposing mice to the CS/US combination on day 0 and reexposing the conditioned animals to the CS on day 2. This results in a conditioned augmentation of the natural killer (NK) cell response. Indomethacin treatment and/or handling stress induced by simply measuring rectal temperature was found to dramatically alter the direction of the conditioned NK cell response. Conditioning of indomethacin treated mice produced a conditioned suppression of the NK cell response mimicking a conditioned tolerance response. If handling stress was superimposed on day 2 the conditioned suppression response was replaced by a conditioned augmentation of the NK cell response. Even with one trial conditioning, drugs and handling stress can serve as additional cues to alter the direction of the conditioned response. The studies also show that the conditioning of the fever response is independent of conditioning of the NK cell response.

Animals↗
PubMedDate not supplied

The General Practice Morbidity Database Project Wales--a methodology for primary care data extraction.

There is a fundamental need for accurate, timely and relevant information for health service planning; the increasing focus on a primary care led NHS has made the collection of information from general practitioners a priority. A collaborative project between general practitioners and public health physicians in Wales has developed methodologies for the extraction and analysis of routinely collected data from general practices across Wales. Four commonly used computer systems have been investigated. This paper outlines the methodologies used and describes the problems encountered and their solutions.

Computer Communication Networks↗
PubMedDate not supplied

Comparison of 5-mm and 6-mm ablation zones in photorefractive keratectomy for myopia.

BACKGROUND: Variation in ablation zone diameter may alter visual acuity and/or refractive effect in photorefractive keratectomy. Despite theoretical benefits of using a smaller diameter ablation zone, clinical studies suggest that a larger ablation zone may decrease problems associated with photorefractive keratectomy. METHODS: The results of our initial 34 consecutive eyes treated with a 5-mm diameter ablation zone using a Summit Technology ExciMed UV200LA excimer laser were compared retrospectively to our initial 34 consecutive eyes treated with a 6-mm diameter ablation zone using a Summit OmniMed excimer laser. Eyes had a spherical equivalent refraction between -1.00 and -6.00 diopters (D) and astigmatism less than 1.00 D. Patients were followed for a minimum of 6 months. RESULTS: Eyes treated with a 6-mm ablation zone had less hyperopia and a spherical equivalent refraction closer to emmetropia at 1, 2, and 3 months (P = 0.001). Eyes treated with a 6-mm ablation zone had better uncorrected visual acuity at 1 and 2 months (P = 0.001). Less subepithelial haze was noted at 2 months (P = 0.01) and 3 months (P = 0.002) in the 6-mm group. At 6 months postoperatively, 30 of 32 eyes (94%) treated with a 6-mm ablation zone had a spherical equivalent refraction within 0.50 D of emmetropia, and all 32 eyes (100%) were within 1.00 D of emmetropia; in the 5-mm ablation zone group, 28 of 34 eyes (80%) were within 0.50 D and 29 (85%) were within 1.00 D of emmetropia. Patients treated with a 6-mm ablation zone complained less of night halos and had fewer differences between night and day vision. CONCLUSIONS: In this study of myopia of -1.00 D to -6.00 D, eyes treated with a 6-mm ablation zone achieve a more rapid visual recovery with less variation in refractive outcome and less adverse effects than those treated with a 5-mm ablation zone.

Adult↗
PubMedDate not supplied

Excimer laser photorefractive keratectomy for hyperopia.

OBJECTIVE: To prospectively study excimer laser correction of hyperopia, with a 1-year followup. METHODS: Eleven consecutive hyperopic eyes (10 phakic and 1 aphakic) underwent correction of hyperopia using the Summit Technology SVS Apex Plus excimer laser. Data collection included cycloplegic refraction, spectacle-corrected visual acuity, contrast sensitivity, corneal haze, manual keratometry, and videokeratography. Prior to treatment the mean hyperopic spherical equivalent refraction (corneal plane) was +5.80 diopters (D) (SD2.10). The mean attempted correction was +3.09 D at the corneal plane. RESULTS: Refractive data for the group showed a mean overcorrection at 1 month of +3.18 D. This regressed slightly before stabilizing at 3 months, with a mean overcorrection of +1.88 D. Thereafter there was no statistically significant fluctuation in refraction (p = 0.67). The amount of overcorrection and regression was greater in eyes that received higher corrections. Changes in manual keratometry and videokeratography mirrored the attempted correction more closely than refraction, although stabilization did not occur until 6 months. CONCLUSIONS: Because the hyperopic correction achieved when measured by refraction was greater than expected, algorithms should be adjusted. The hyperopic erodible disc and Axicon lens system is capable of treating low to moderate amounts of hyperopia.

Adult↗
PubMedDate not supplied

Intraocular lens power calculation for cataract surgery after photorefractive keratectomy for high myopia.

OBJECTIVE: To assess intraocular lens (IOL) power calculations in patients undergoing cataract surgery after excimer laser photorefractive keratectomy (PRK) for myopia. METHODS: Four eyes of two patients underwent phacoemulsification with IOL implantation after PRK for myopia. The estimated refractive error that would have been induced had the IOL predicted for emmetropia been implanted was calculated using SRK-II, SRK/T, Holladay, and Binkhorst formulas. Manual keratometry and videokeratography-simulated keratometry values measured before surgery were used. Keratometry values calculated by subtracting the refractive change induced by the excimer laser PRK from the manual keratometry or videokeratography-simulated keratometry values measured before PRK were also used. Both spectacle and corneal plane calculations were performed. RESULTS: Manual keratometry and videokeratography-simulated keratometry values underpredicted the IOL power. Corneal plane manual or videokeratography refraction-derived keratometry calculations were most accurate using the SRK/T formula, while spectacle plane calculations were most accurate using the SRK-II formula. In both methods the calculated refractive error was within 0.52 diopters (D) for the emmetropic lens power predicted. Statistical analysis was not performed. CONCLUSIONS: Refraction-derived keratometric values provided the most accuracy in calculating IOL powers. Our results suggest the SRK/T formula was the most accurate for corneal plane calculations, while the SRK-II formula was the most accurate for spectacle plane calculations.

Cornea↗
PubMedDate not supplied

Assessment of electric differential treatment (EDiT) and Endosan treatment for ovarian cysts and concomitant symptoms.

The mechanisms of action and clinical applications of electric differential treatment (EDiT) and Endosan in the treatment of ovarian cysts and concomitant symptoms are reviewed. Possible mechanisms of action include an increased level of cyclic AMP, stimulation of endorphin release, anti-inflammatory action, and steroidogenesis resulting from normalization of intercellular communication. Favorable results in the clinical setting were achieved in the treatment of ovarian cysts. Treatment success was reflected in a significant reduction in overall cyst size as well as amelioration of various concomitant symptoms, including fever, chills, inflammation, and abdominal pain. EDiT and Endosan were shown to have potent analgesic and anti-inflammatory effects. No adverse effects have been reported.

Adolescent↗