Donor eyes. A comparison of characteristics and outcomes for Eye Bank and local tissue

The Corneal Recipient Registry was begun in 1985 to collect information on all recipients of corneal grafts in the province of Ontario, Canada, and on the donors providing tissue. While most of the tissue is handled by the Eye Bank of Canada (Ontario Division), ophthalmologists in centers away from the Eye Bank often use local tissue when it is available. Comparison of the donor characteristics of local tissue with that obtained through the Eye Bank revealed that local donors were 9-10 years younger (p less than 0.01), their times to enucleation were an hour less (p less than 0.02), and they were much more likely to be the victims of trauma than the donors of Eye Bank eyes. Prognosis of the graft, assessed using life table methods, suggested that success of local eyes was 89% after 6 months, compared with 80% for Eye Bank eyes in the same period, but this was not a significant difference (p greater than 0.05). While the Eye Bank is a more common source of tissue, eyes obtained locally are more likely to represent the "ideal" tissue for many corneal surgeons.     

Mortality in patients with successful initial response to highly active antiretroviral therapy is still higher than in non-HIV-infected individuals

Mortality in HIV-infected patients has decreased dramatically since the introduction of highly active antiretroviral therapy (HAART). We analyzed progression to death in a population of 3678 antiretroviral treatment-naive patients from the ATHENA national observational cohort from 24 weeks after the start of HAART. Mortality was compared with that in the general population in the Netherlands matched by age and gender. Only log-transformed CD4 cell count (hazard ratio [HR] = 0.50, 95% confidence interval [CI]: 0.40 to 0.61 per unit increase) and plasma viral load (HR = 0.30, 95% CI: 0.15 to 0.60, HIV RNA level <100,000 vs. > or = 100,000 copies/mL) measured at 24 weeks and infection via intravenous drug use (IDU) (HR = 0.16, 95% CI: 0.10 to 0.26, non-IDU vs. IDU) were significantly associated with progression to death. For non-IDU patients with 600 x 10 CD4 cells/L and an HIV RNA level <100,000 copies/mL at 24 weeks, mortality was predicted to be 5.3 (95% CI: 3.5 to 8.4) and 10.4 (95% CI: 6.4 to 17.4) times higher than in the general population for 25-year-old men and women, respectively, and 1.15 (95% CI: 1.08 to 1.25) and 1.29 (95% CI: 1.16 to 1.50) times higher for 65-year-old men and women, respectively. Hence, mortality in HIV-infected patients with a good initial response to HAART is still higher than in the general population.     

An association between variants in the IGF2 gene and Beckwith-Wiedemann syndrome: interaction between genotype and epigenotype

Beckwith-Wiedemann syndrome (BWS) is a fetal overgrowth disorder involving the deregulation of a number of genes, including IGF2 and CDKN1C, in the imprinted gene cluster on chromosome 11p15.5. In sporadic BWS cases the majority of patients have epimutations in this region. Loss of imprinting of the IGF2 gene is frequently observed in BWS, as is reduced CDKN1C expression related to loss of maternal allele-specific methylation (LOM) of the differentially methylated region KvDMR1. The causes of epimutations are unknown, although recently an association with assisted reproductive technologies has been described. To date the only genetic mutations described in BWS are in the CDKN1C gene. In order to screen for other genetic predispositions to BWS, the conserved sequences between human and mouse differentially methylated regions (DMRs) of the IGF2 gene were analyzed for variants. Four single nucleotide polymorphisms (SNPs) were found in DMR0 (T123C, G358A, T382G and A402G) which occurred in three out of 16 possible haplotypes: TGTA, CATG and CAGA. DNA samples from a cohort of sporadic BWS patients and healthy controls were genotyped for the DMR0 SNPs. There was a significant increase in the frequency of the CAGA haplotype and a significant decrease in the frequency of the CATG haplotype in the patient cohort compared to controls. These associations were still significant in a BWS subgroup with KvDMR1 LOM, suggesting that the G allele at T382G SNP (CAGA haplotype) is associated with LOM at KvDMR1. This indicates either a genetic predisposition to LOM or interactions between genotype and epigenotype that impinge on the disease phenotype.     

Propionyl coenzyme A carboxylase deficiency presenting as non-ketotic hyperglycinaemia.

A 4-month-old girl presented with myoclonic seizures and an electroencephalogram showing hypsarrhythmia. Hyperglycinuria and a cerebrospinal fluid to plasma glycine ratio of 0.2 suggested the diagnosis of non-ketotic hyperglycinaemia. Propionic acid and methyl citric acid were present in the urine, and propionyl coenzyme A carboxylase was deficient in leucocytes and fibroblasts. The ketotic and non-ketotic hyperglycinaemias cannot be differentiated by CSF: plasma glycine ratios.     

Postnatal development of the mouse dentate gyrus in organotypic cultures of the hippocampal formation

The hippocampal formation of newborn mice was explanted and maintained in Maximow culture assemblies for up to 35 days. At the time of explantation, only the suprapyramidal limb of the dentate gyrus was cytoarchitectonically distinct, and electron microscopy of newborn hippocampus revealed no definitive synapses. Histogenesis, as indicated by the development of the infrapyramidal limb of the dentate gyrus, and synaptogenesis, as indicated by the in vitro formation of mossy fiber synapses on the dendrites of hippocampal pyramidal neurons were studied by light and electron microscopy. At 12 days and thereafter in culture, mossy fiber terminals were found in synapsis with dendritic spines probably belonging to pyramidal cells of the hippocampal zone CA4. Near dentate granule cell somata a few axosomatic and many axospinous and axodendritic synapses were found. The data indicate that granule cells of the developing dentate gyrus are capable of differentiation in vitro into a structure essentially equivalent to that developed in vivo. The granule cells may become arranged into a recognizable granule cell layer, and develop dendritic processes which receive synapses virtually identical to those found in the intact organ. The differentiation of these features proceeds in the absence of the extrinsic afferents from the septum or from the contralateral hippocampal formation.     

Potentiation of lymph node antibody synthesis by normal thymus in vitro

Antibody formation during the secondary response in vitro was enhanced when normal thymus fragments from 1- to 2-week-old rabbits were coincubated with immune popliteal lymph node fragments. Although the addition of three thymus fragments to three lymph node isolates produced a significant increase in antibody synthesis, six or nine thymus fragments stimulated the response still further; normal spleen or normal lymph node did not stimulate. Radioactive amino acid incorporation into antibody confirmed that de novo antibody synthesis was potentiated by the thymus. In addition, increased synthesis of total globulins was quantitatively measured. The thymus seemed to enhance formation of only 7S immunoglobulin as determined by sucrose gradient centrifugation. It is not known whether thymus cells, humoral factors, or both participate in this response, or what intracellular metabolic events are being stimulated when the thymus is added to the cultures.     

CD5 (OKT1) augments CD3-mediated intracellular signaling events in human T lymphocytes

CD5 is expressed on thymocytes, all mature T cells, and a subset of mature B cells, and probably contributes to T-cell–B-cell adhesion. We assessed whether CD5-crosslinking by mAb augments T-cell stimulation. Plate-bound anti-CD5 or anti-CD3 mAb alone had no effect on any of the assessed activation parameters of resting T cells. However, concomitant signaling through both CD5 and CD3 by plate-bound antibodies resulted in marked increases in T-cell surface CD69 expression and T-cell metabolism, as assessed by the T cell's ability to reduce 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxylmethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium (MTS) to formazen. In addition, simultaneous cross-linking of CD5 and CD3 caused a significant (p < 0.001) increase in phosphatidylinositol hydrolysis in resting T cells compared to stimulation with anti-CD3 mAb alone or anti-CD3 mAb plus anti-CD5 isotype control antibody. These results indicate that CD5 augments signaling through CD3 and consequently functions as a costimulatory molecule for resting T cells.     

Susceptibility of mice to rotavirus infection: effects of age and administration of corticosteroids.

We examined susceptibility to the murine rotavirus, epizootic diarrhea of infant mice virus (EDIM), in normal suckling and weaned mice and in suckling mice treated with glucocorticoids. Normal mice 1 to 40 days old were inoculated by gastrin intubation with high doses of EDIM and subsequently evaluated for rotavirus infection by solid-phase radioimmunoassay, by electron microscopy of intestinal tissue sections or by both. Radioimmunoassay and electron microscopy showed a concordance of 89.5% in the detection of rotavirus infection. After a period of low susceptibility to EDIM infection during the first 3 days after birth (23%), susceptibility was high for the next 11 days (95%), but decreased abruptly as mice approached weaning (41% on days 15 through 17). Mice 34 days or older did not develop EDIM infection after inoculation, but rotavirus antigen was detected in 12% of uninoculated mothers nursing inoculated litters. Administration of cortisone acetate to 8-day-old mice induced partial intestinal maturation prematurely. At 3 to 6 days after cortisone acetate treatment, susceptibility to EDIM infection decreased to 60% compared with 94% in age-matched controls. Our data suggest (i) that susceptibility of mice to EDIM infection is age dependent, decreasing in concert with intestinal maturation, and (ii) that glucocorticoids, which induce premature partial intestinal maturation, modulate susceptibility of mice to EDIM.