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Biomedical subjects

D Chandler

Publications and source records attributed to D Chandler.

At least 73 records · Page 4Linked to original sources
PubMed1992

Acquired resistance in Arabidopsis.

Acquired resistance is an important component of the complex disease resistance mechanism in plants, which can result from either pathogen infection or treatment with synthetic, resistance-inducing compounds. In this study, Arabidopsis, a tractable genetic system, is shown to develop resistance to a bacterial and a fungal pathogen following 2,6-dichloroisonicotinic acid (INA) treatment. Three proteins that accumulated to high levels in the apoplast in response to INA treatment were purified and characterized. Expression of the genes corresponding to these proteins was induced by INA, pathogen infection, and salicylic acid, the latter being a putative endogenous signal for acquired resistance. Arabidopsis should serve as a genetic model for studies of this type of immune response in plants.

Amino Acid Sequence↗
PubMed1992

Responses of first-grade children to concepts about printed material before and after shared reading experiences.

A study was conducted to investigate the effects of shared reading experiences using books with predictable content to assess 24 inner-city African-American first-graders' concepts about printed material. The 8-week treatment using a two-group pre- and posttest experimental design with random assignment showed no significant differences between groups. A larger sample and longer treatment time are recommended for replicating this study.

Child↗
PubMed1990

Glutathione S-transferase. Novel vaccine against Fasciola hepatica infection in sheep.

The potential of GST as a vaccine candidate against liver fluke infection in ruminants was studied by vaccinating sheep (n = 9) with GST purified from adult worms of Fasciola hepatica and challenging with 500 F. hepatica metacercariae. The immunization induced a high antibody response to GST in contrast to the poor or undetectable response to this Ag observed in naturally infected sheep. Throughout the trial, the progress of the fluke infection was monitored by measuring RBC hemoglobin levels, the extent of liver damage and the fecal egg output in the sheep. This analysis indicated that a subpopulation (n = 4) of the GST vaccinated animals exhibited no anemia, reduced liver damage and a lower mean fecal egg count relative to the infected control group suggesting a lower fluke burden in these animals. Worm burdens in the livers of the GST vaccine group (107 +/- 22) were 57% lower than in the infected control group (250 +/- 25). The subpopulation of the GST vaccine group demonstrated a 78% reduction in mean worm burdens relative to the control group. These results show that GST of adult F. hepatica is a novel Ag that can significantly protect sheep against liver fluke infection. The results suggest that the immune response to GST is directed to the juvenile worm reducing the number of worms that can establish in the liver of the vaccinated animals.

Animals↗
PubMed1990

Clinical and histologic effects of extreme intraocular hypothermia.

Rabbit eyes in which vitrectomy was performed underwent three hours of hypothermic perfusion with either 22 C or 2 C lactated Ringer's solution. Clinical, electroretinographic, fluorescein angiographic, histologic, and ultrastructural examinations were performed. No changes were noted in eyes cooled with 22 C fluid. Reversible lens opacities, equivocal electroretinographic changes, and subclinical retinal detachments were found in the eyes cooled with 2 C fluid. Extreme cooling of eyes is not advisable, although temperatures of 22 C are well tolerated.

Animals↗
PubMed1990

Reduction of basement membrane thickening in diabetic cat retina by sulindac.

Capillary basement membrane thickening is one of the earliest histologic lesions in diabetic retinopathy. Its pathogenesis is not understood; however, recent evidence suggests that aldose reductase may play a role. In this study, a new animal model, the diabetic cat, was used to determine whether retinal capillary basement membrane thickening occurred early in the course of hyperglycemia, and if so, whether it could be inhibited by sulindac, an aldose reductase inhibitor. Retinal capillary basement membrane thickness was significantly increased in diabetic cats compared to normal cats (114 +/- 15 vs 72 +/- 12 nm, mean +/- SD) [corrected]. Basement membrane thickness was significantly less in sulindac-treated diabetic cats (93 +/- 9 nm) compared to the untreated diabetic cats (114 +/- 15 nm). In addition, quantitation of endothelial cells, pericytes, and contacts between endothelial cells and pericytes in electron micrographs revealed that they were not reduced in number in untreated diabetic cats compared to normal or sulindac-treated diabetic animals.

Animals↗
PubMed1989

Palmar shelf arthroplasty in the rheumatoid wrist. Results of long-term follow-up.

Sixty-three palmar-shelf arthroplasties (so-called pseudofusions of the wrist) that had been performed between 1970 and 1978 in forty-nine patients were evaluated. The length of follow-up averaged eighty-three months (minimum, twelve months for the wrists that fused and twenty-four months for those that did not). Preoperatively, all wrists were painful, with 96 per cent being moderately or severely so. Carpal subluxation was present in 79 per cent of the wrists. Postoperatively, pain recurred in 84 per cent of the wrists, but it was less severe (mild in 48 per cent, moderate in 35 per cent, and severe in 2 per cent). Sixty-eight per cent of the wrists fused spontaneously and were no longer painful. Of the twenty wrists (32 per cent) that did not fuse, 70 per cent were mildly or moderately painful. In patients who have rheumatoid arthritis, we found that palmar shelf arthroplasty was followed by a high rate of delayed spontaneous fusion and an unacceptably high rate of recurrent pain, although the pain was less severe.

Arthritis, Rheumatoid↗
PubMed1988

Results of 21 Wagner limb lengthenings in 20 patients.

Roentgenograms and charts were reviewed on 20 patients (average age: 13.2 years) who had 21 Wagner limb lengthenings since 1975. Lengthenings included 15 femora (six acquired, eight congenital, and one fibrous dysplasia), four tibiae, and two humeri (one acquired and one congenital). Average femoral lengthening was 6.6 cm; tibial, 5.9 cm; and humeral, 9.7 cm. Lengthening of femora with congenital shortening (6.5 cm) was nearly the same as femora with acquired shortening (6.8 cm), and 85% of all lengthenings were greater than 5 cm. Humeri were lengthened more than 50%. Seventy-two percent of patients were in the 50th percentile or less of stature; 61% were in the 15th percentile or less of stature. Seventy-five percent had complications, with 65% having more than one major complication: pin tract and superficial infections in 40%; deep infections in 20%. All infections were in femoral lengthenings. Nonunion occurred in two patients (10%), and fracture after plate removal in two patients (10%). Five patients (25%) had nerve palsies, and four of these resolved without treatment. Malunion rate was 20%. Five patients developed joint contractures. Complications did not correlate with amount of lengthening but congenital deformities had a higher incidence of complication. Eleven patients required 19 additional procedures necessitated by the lengthening procedure. Wagner leg lengthening is generally recommended when amputation is only other surgical alternative and a full, complete informed consent is given to the parents and patient.

Adolescent↗
PubMed1986

Temperature-dependent light damage to the retina.

We examined the ability of hypothermic infusion fluid to reduce the risk of light damage to the retina from the intraocular fiberoptic probe during vitreous surgery. Following vitrectomy, we exposed the retina of rabbits to light from an intraocular fiberoptic probe during infusion of fluid at body temperature (39 C) and compared this with exposures during infusion of room temperature fluid (22 C). Retinal irradiance was 0.33 W/cm2. Damage was determined ophthalmoscopically and histologically. Cooling the infusion fluid from body to room temperature extended the damage threshold from approximately 25 to 60 minutes. A 35-minute exposure to body temperature fluid was compared with the same exposure during infusion of room temperature fluid. While retinal and retinal pigment epithelium damage was present after the body temperature exposure, no damage was detected after the room temperature exposure. Vitreoretinal surgeons should avoid warming intraocular infusion fluids to levels above room temperature.

Animals↗
PubMed1986

Experimental and clinical observations of the intraocular toxicity of commercial corticosteroid preparations.

We tested the vehicles of six different commercially available depot corticosteroids (Celestone Soluspan, Depo-Medrol, Decadron, Decadron L. A., Aristocort, and Kenalog) for possible toxicity when injected intravitreally. When tested on rabbit eyes, the Celestone Soluspan and the Depo-Medrol vehicles caused remarkable retinal degeneration with preretinal membrane formation or cataracts in their standard concentrations. Three other vehicles (Decadron and Decadron L. A.) caused localized retinal degeneration in twice the standard concentration. Thus, toxic effects can be caused by preservatives or inadequate osmolarity of the vehicles alone. The development of proliferative vitreoretinopathy in some cases of injections of intraocular depot corticosteroid can be explained by retinal necrosis and repair processes caused by these vehicles.

Adrenal Cortex Hormones↗
PubMed1985

Isoimmune neonatal thrombocytopenia: a case report and review.

Isoimmune neonatal thrombocytopenia is an unusual problem with significant morbidity and mortality. Though it is often self-limited, it is potentially fatal due to hemorrhage. Specific therapy with compatible platelets is indicated. In previously unrecognized cases, platelet antigen and antibody studies delay therapy unacceptably. Therefore, maternal platelets are used, which also aid in establishing a therapeutic diagnosis. A case of isoimmune neonatal thrombocytopenia is reported, and the etiology, clinical and laboratory implications, and methods of management are discussed.

Adult↗
PubMed1984

Pathogenesis of capsular opacification after extracapsular cataract extraction. An animal model.

Opacification of the posterior capsule is the most common post-operative complication of extracapsular cataract surgery. We studied the sequential changes in the posterior capsule of the aphakic cat and monkey after extracapsular surgery using light microscopy, scanning electron microscopy, and transmission electron microscopy. In the cat, but not the monkey, there was proliferation of a pigment-containing membrane arising from the iris root and ciliary body, and extending onto the residual lens capsule. In both animals there was transformation of residual lens epithelial cells to fibroblasts which contain contractile elements (myofibroblasts) and are associated with collagen deposition. In the cat, pigment epithelial cells from the iris or ciliary body, as well as the transformed lens epithelial cells, contributed to late opacification of the posterior capsule.

Animals↗