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Biomedical subjects

C A Rogers

Publications and source records attributed to C A Rogers.

At least 55 records · Page 3Linked to original sources
PubMed1994

Corneal graft survival and visual outcome. A multicenter Study. Corneal Transplant Follow-up Study Collaborators.

PURPOSE: The Corneal Transplant Follow-up Study has followed 2385 corneal transplants performed in the United Kingdom and the Republic of Ireland for up to 450 days to quantify factors influencing corneal graft survival and visual outcome 3 and 12 months postoperatively. METHODS: Multifactorial analyses of grafts registered by United Kingdom Transplant Support Service from July 1987 to June 1990 were used. Corrected visual acuity of functioning grafts was assessed at 3 and 12 months. RESULTS: Of 2385 corneal transplants followed, 214 failures were observed: graft survival was 95% at 3 months and 89% at 1 year. Similar factors affected outcome at each time. Decreased risk of failure was associated with surgeons reporting most grafts, and increased risk was associated with regrafts, patients younger than 10 years of age, nonvisual reasons for grafting, endothelial failure, and deep vascularization. Visual outcome was worse in older patients and was associated with cosmetic reasons for grafting, superficial vascularization preoperatively, and secondary endothelial failure. Visual acuity was better when the other eye had been grafted previously, or when the diagnosis was keratoconus or stromal dystrophy. CONCLUSIONS: Primary endothelial failure was associated with high failure rates but good visual results when functioning. Most other factors had similar effects on both outcome measures. Improved outcome under highest-reporting surgeons was slight, and indicated possible differences in postoperative care.

Adolescent↗
PubMed1993

Corneal transplantation in the United Kingdom and Republic of Ireland.

The Corneal Transplant Follow up Study has registered 4560 corneal grafts performed in the United Kingdom and Republic of Ireland from July 1987 to June 1991. Rates of reported grafts doubled during that time. This increase was greater for surgeons and regions reporting fewer grafts, but was consistent across patient factors. Eleven of 428 consultants were responsible for over 25% of grafts, and their patients' characteristics differed significantly from others. Overall, reasons for grafting were visual only (77%), visual and other (16%), and non-visual (7%). Most frequent diagnoses were endothelial failure (38%), inflammation (26%), and keratoconus (20%). Age ranged from 2 months to 97 years, and differed markedly with diagnosis. Eighteen per cent of transplants were regrafts, and 40% were vascularised preoperatively.

Adolescent↗
PubMed1993

Penetrating keratoplasty in the United Kingdom: an interim analysis of the corneal transplant follow-up study.

1. Clinical corneal transplantation has been performed for over a century, but many elements leading to a successful outcome have yet to be identified. 2. Because there are limitless supplies of tissue, the supply of corneas need never fall short of demand. Nevertheless, retrieval rates vary widely among regions in the UK due to uneven organization of services. 3. Organ culture of corneas improves the quality of transplanted tissues because it allows time for substandard material to be discarded. The outcome appears to equal other storage methods. 4. Between 1987 and 1991, 4,560 corneal transplants were performed by 428 surgeons at 216 centers in the UK and were registered with CTFS. Of these, 3,213 were evaluable for graft survival, rejection, and other measures of visual outcome. 5. Unifactorial analysis revealed that the percentage of graft survival at one year was 89% and rejection-free survival was 87%. However, the hazard of rejection appeared to increase at or after the time of suture removal. 6. The percentage of recipients in whom CVA was 6/24 or better (able to read normal text with correction) improved from 16% preoperatively to 59% at 3 and 70% at 12 months postoperatively overall. In patients transplanted purely for visual reasons, improvement was 78% and 83% at 3 and 12 months, respectively. 7. Interim results of multifactorial analysis suggest that the risk of graft failure, rejection, and decreased CVA increased in association with the following factors: surgeons who reported fewer than 50 transplants to the study; recipients under 10 years of age; previously failed grafts (the more failed grafts, the greater the risk); grafting for nonvisual reasons; certain diagnoses; and vascularization of the corneal bed prior to transplantation. 8. Astigmatism was investigated in 880 cases at 3 months postoperatively. Preliminary analysis indicated that the risk of severe astigmatism was influenced by suturing technique and large differences between (> 0.25 mm) donor and recipient trephine size. 9. The effects of HLA matching were evaluated in 542 transplants. HLA-A and B matching reduced the risk of rejection during the first 450 days posttransplant, but HLA-DR matching appeared to increase the risk of rejection. 10. A rat model designed to simulate clinical corneal grafting was used to investigate the interaction between immunosuppression and matching. Whereas MHC mismatching could be overcome with topical dexamethasone, non-MHC mismatching appeared resistant.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Renal transplantation in highly sensitized patients: five years of the SOS Scheme.

1. One-year graft survival of 218 patients transplanted through the SOS Scheme for highly sensitized recipients was 65%. There was significant improvement in the graft survival of 135 patients transplanted from 1986 to 1988, compared to the 83 patients transplanted from 1984 to 1985 (70% vs 56% at 1 year). 2. Of the 513 patients entered into the SOS Scheme, 218 (42%) received a graft, and of those 218, 179 were transplanted within 1 year. 3. Sex and previous graft history influenced the patient's sensitization status. Males with previously failed grafts and females waiting for their first transplant appeared at greater risk of becoming highly sensitized. 4. HLA matching improved graft survival in highly sensitized patients. The effect of matching was most evident for DR and for HLA-B and DR combined. The effect of matching for HLA-A was minimal. 5. HLA-DR1-positive individuals appeared to be at lower risk of becoming highly sensitized. In addition, DR1-positive highly sensitized patients had superior graft survival compared to DR1 negative recipients.

Graft Survival↗
PubMed1990

Identification, characterization, and photoaffinity labeling of the dihydropyridine receptor associated with the L-type calcium channel from bovine adrenal medulla.

The dihydropyridine receptor associated with the L-type Ca2+ channel in adrenal medulla membranes has been identified and characterized. [3H]PN200-110 binds in a stereoselective, saturable manner to a single class of high affinity sites in adrenal medulla membranes, with a Kd of 0.1 nM and a Bmax of 141 fmol/mg of protein. Dihydropyridines inhibited [3H]PN200-110 binding with the rank order (+)-PN200-110 greater than nifedipine greater than nimodipine greater than usoldipine greater than or equal to nitrendipine greater than BayK8644 greater than (-)-PN200-110. [3H] PN200-110 binding was sensitive to divalent cations, as examined by the effects of Ca2+, Mg2+, and the chelators ethylene glycol bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and EDTA. [3H]PN200-110 binding was modulated by various classes of L-type Ca2+ channel effectors. Benzothiazepines modulated binding of [3H]PN200-110 in a negative or positive manner that was temperature dependent, whereas phenylalkylamines weakly inhibited [3H]PN200-110 binding. Bepridil stimulated [3H] PN200-110 binding, whereas phencyclidine was without effect. The photoaffinity probe [3H]azidopine labeled a single polypeptide that migrated with an apparent molecular weight of 185,000-190,000 in sodium dodecyl sulfate gel electrophoresis. The dihydropyridine receptor was found to bind specifically to wheat germ agglutinin columns. These results demonstrate the presence of a Ca2+ channel blocker complex in adrenal medulla. The drug receptor sites reside on a glycoprotein complex in which a polypeptide analogous to the alpha 1-subunit of the L-type Ca2+ channel from skeletal muscle has been identified.

Adrenal Medulla↗
PubMed1983

Indium-111 chloride imaging in patients with suspected abscesses: concise communication.

Two hundred and fifty-eight patients with clinically suspected inflammatory processes were studied. Seventy-two images were categorized as true positive; 211 as true negative. There were nine false-positive studies, four of which were due to activity in beds of excised organs. There were six false-negative studies, four of which were due to walled-off abscesses found either at surgery or biopsy. The sensitivity was 92%, the specificity 95%, and the accuracy 94%. This study shows that indium-111 chloride imaging provides a reliable way to locate inflammatory processes and overcomes the disadvantages of other imaging agents, for example gastrointestinal activity or the demonstration of healing surgical wounds with gallium-67, and the false-positive images due to cystic fibrosis and other respiratory diseases, or accessory spleens as seen with In-111-labeled white cells.

Abscess↗
PubMed1979

Relationship of Temperature to Stomatal Aperture and Potassium Accumulation in Guard Cells of Vicia faba.

Epidermal strips of Vicia faba were floated on 10 millimolar KCl at various temperatures and for several time periods. The diameter of the stomatal aperture was determined microscopically and K(+) content was estimated and expressed as the per cent of the guard cell stained. Stomatal opening was associated with increased K(+) in guard cells, but the quantitative association was modified both by time and temperature. At low temperatures (0-20 C) there was a prolonged Spannungsphase while at higher temperatures (30-45 C) motorphase was exhibited. During the motorphase there was a rapid opening of the stomates which was highly correlated with K(+) influx. At treatment periods of 360 minutes and temperatures higher than 25 C there appeared to be a maintenance phase during which K(+) concentration of the guard cells decreased without an equivalent decrease in aperture.

Journal Article↗
PubMed1979

Effect of varying picture-sentence congruence on children's free recall.

70 fourth-grade children were shown objects arbitrarily arranged in an integrated scene. Subjects were randomly assigned to conditions which either presented a sentence that correctly labeled and correctly described the physical arrangement of the objects, presented a sentence containing the correct labels of the objects but not the correct physical arrangement, or presented a sentence which did not contain the correct labels and incorrectly described the physical arrangement. Control conditions either provided subjects with correct labels or omitted presentation of verbal prompts. Congruence between the object display and the sentence produced significantly higher recall and clustering than the incongruence or control conditions. The incongruence conditions did not produce significantly higher recall than the control conditions, suggesting that incongruence interferes with formation of stable grouping of items which appears to be an important factor in facilitating free recall.

Child↗