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Biomedical subjects

K Hanna

Publications and source records attributed to K Hanna.

51 records · Page 3Linked to original sources
PubMed1987

Financing of child psychiatry pediatric consultation-liaison programs.

Child psychiatrists and pediatricians recognize the importance of providing psychosocial care for children and their families in medical settings. Consultation-liaison and behavioral pediatric programs provide most of the training in this area. Twenty-nine pediatric consultation-liaison program directors participated in an initial and follow-up telephone survey about their programs. In the 5 years between the surveys, there was a drastic reduction in federal funding for these programs. The findings include a change in the number and composition of both staff and trainees. There were major shifts in the financial support of the programs. The programs were involved in fewer activities and in more restricted settings at the time of the follow-up survey. Financing of pediatric consultation-liaison programs plays a major role in shaping the structure and function of the programs.

Child↗
PubMed1987

Excimer laser experimental keratectomy. Ultrastructural study.

Excimer lasers have been shown to produce precise etching and clean incisions of the cornea. On two freshly enucleated human eyes radial incisions and a myopic keratomileusis were performed with a specially designed delivery system. The cornea was then studied by transmission and scanning electron microscopy. The surface of the irradiated area was extraordinarily smooth and clean with a precision greater than 10 nm. The epithelial cells were literally cleaved by the ablation process. The cytoplasm and the nucleus were cut without any damage to the other part of the cell and no disturbance of the cells proximal to the incision. The corneal stroma was cut in a regular and smooth fashion, and the aspects observed with the scanning electron microscope differed mainly from the surface observed after an incision made with a diamond knife. The excimer laser allowed optimal conditions for quick and safe wound healing but the long-term effects on the epithelial cells must be evaluated by further studies.

Cornea↗
PubMed1986

Effect of dietary vitamin E on the vitamin E status in the BB rat during development and after the onset of diabetes.

Weanling diabetes-prone BB rats were fed AIN-76 diets containing high (HE, 1 g/kg diet), basal (NE, 0.2 g/kg) or low (LE, trace) vitamin E and were killed at 21, 42 or 60 days of age. Plasma and tissues (adrenals, pancreas, spleen, thymus, liver, brown and white adipose tissue, muscle and testes) were analysed for vitamin E. Vitamin E levels reflected the level in the diet and no diabetic animals were detected at these times. In a second experiment, a total of 90 diabetes-prone BB rats were kept on diets LE and HE for 6 months or until they became diabetic. 11/45 on LE and 5/45 on HE became diabetic. Again, plasma and tissue levels of vitamin E reflected the levels in the diet with the exception of the thymus of diabetic rats fed the high vitamin E diet. Thymus vitamin E levels (microgram/g tissue) were 1.8 and 1.2 in LE-fed diabetics and asymptomatic rats, respectively; and 22.7 and 49.5 in HE-fed diabetics and asymptomatic rats, respectively. The last 2 values were significantly different (p less than 0.005). There were no other differences in plasma or tissue levels of vitamin E in these groups of animals. These findings suggest that high dietary vitamin E may decrease the incidence of diabetes in animals which are able to accumulate sufficient amounts of the vitamin in the thymus. Since the thymus plays a key role in the maturation of T cell populations, which appear to be altered in this disease, it seems possible that the protective effect may be exerted at this level.

Adipose Tissue↗
PubMed1983

HLA-A, -B, and -DR antigens in North African patients with nasopharyngeal carcinoma.

Seventy-six North African patients (most from Algeria) affected with nasopharyngeal carcinoma (NPC) have been studied for their HLA-A, -B, and -DR phenotypes and compared with a control North African population. Antigens HLA-A3, HLA-B5 and HLA-Bw15 were found more frequently in the NPC group than in the control group (30.3% vs 17.6%, 38.2% vs 24.4% and 9.2% vs 0.8%, respectively). HLA-Aw33, HLA-B14 and HLA-DR4 were less frequent in the patients than in the controls (3.9% vs 16.8%, 1.3% vs 16% and 13.2% vs 29.1%, respectively). After correction for the number of specificities tested, these differences were not statistically significant. They were, however, more striking when compared to normal Kabyles (Algerian Berbers), a major ethnical population in Algeria, with lower incidences of the HLA-B5 antigen and of the HLA-Aw33-B14 haplotype. This could suggest, in North Africa, either the existence of MHC-linked genes of resistance or susceptibility to NPC, in Berbers especially, or a preferential occurrence of NPC in non-Berbers. Antibody titers against the Epstein-Barr virus (EBV) associated early antigen (EA) and viral capsid antigen (VCA) have been measured. No correlation was observed between HLA phenotypes and the anti-EBV serological response of the patients.

Adolescent↗
PubMedDate not supplied

Current status of synthetic epikeratoplasty.

Many of the deficiencies with human tissue epikeratoplasty might be improved by the use of a suitable synthetic lenticule. Potential biomaterials for epikeratoplasty include collagen (types I, III, or IV), collagen-hydrogel copolymers, bioactive synthetics, and coated hydrogels. The biomaterial must be engineered to achieve strict specifications of optical clarity, support of epithelial migration and adhesion, permeability to solutes, and stability to corneal proteases. Attaching synthetic lenticules to the cornea without cutting Bowman's layer by adhesives, laser welding, or direct adhesion may also improve the efficacy of synthetic epikeratoplasty.

Animals↗
PubMedDate not supplied

[Trephination using an Excimer laser].

We compared histologically and ultrastructurally donor buttons and recipient beds trephined mechanically with those trephined by the Excimer laser at 193 nm. The laser allowed for superior cutting precision and perfect centering. This non-contact method obviated the need for any pressure or suction during trephination, thereby eliminating problems associated with distortion of corneal topography. We studied wound healing after penetrating keratoplasty with mechanical and laser trephination in an animal model. The laser did not adversely affect wound healing processes.

Animals↗