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Biomedical subjects

T del Rio

Publications and source records attributed to T del Rio.

11 recordsLinked to original sources
PubMed2002

The pseudorabies virus VP22 homologue (UL49) is dispensable for virus growth in vitro and has no effect on virulence and neuronal spread in rodents.

The tegument of herpesvirus virions is a distinctive structure whose assembly and function are not well understood. The herpes simplex virus type 1 VP22 tegument protein encoded by the UL49 gene is conserved among the alphaherpesviruses. Using cell biology and viral genetics, we provide an initial characterization of the pseudorabies virus (PRV) VP22 homologue. We identified three isoforms of VP22 present in PRV-infected cells that can be resolved by polyacrylamide gel electrophoresis. The predominant form is not phosphorylated and is present in virions, while the other two species are phosphorylated and excluded from virions. VP22 localized to the nucleus by 6 h postinfection, as determined by immunofluorescence and cell fractionation. VP22 immunofluorescence in the nucleus was both diffuse and in punctate structures. The punctate nuclear localization was the most pronounced form of staining and did not localize exclusively to sites of viral DNA replication. Unexpectedly, a VP22 null mutant had no obvious phenotypes during tissue culture infections and was similar to the wild type in all respects. Moreover, the VP22 null mutant was as virulent and neuroinvasive as the wild-type virus after infection of the rodent eye and spread to the brain using both anterograde and retrograde neuronal circuits.

Animals↗
PubMed2001

Decrease in tear secretion and corneal sensitivity after laser in situ keratomileusis.

PURPOSE: To evaluate tear secretion and corneal sensitivity after laser in situ keratomileusis (LASIK) for the correction of myopia. METHODS: In a prospective study, 48 consecutive eyes (24 patients) underwent LASIK to correct myopia ranging from -3.5 to -12.25 diopters. Tear secretion tested by the tear function index and corneal sensitivity tested using the Cochet-Bonnet esthesiometer were evaluated preoperatively and 1 week and 1, 3, 6, and 9 months postoperatively. RESULTS: Tear secretion and corneal sensitivity after LASIK were reduced during the first 3 months after surgery (p<0.001). Tear secretion returned to its preoperative values only after 9 months. Tear secretion and corneal sensitivity were more depressed in long-term contact lens wearers preoperatively and 6 months after surgery (p<0.05). CONCLUSION: In the correction of myopia, tear secretion was depressed after LASIK during the first 6 months after surgery.

Adult↗
PubMed2000

Genetic and epigenetic incompatibilities underlie hybrid dysgenesis in Peromyscus.

Crosses between the two North American rodent species Peromyscus polionotus (PO) and Peromyscus maniculatus (BW) yield parent-of-origin effects on both embryonic and placental growth. The two species are approximately the same size, but a female BW crossed with a male PO produces offspring that are smaller than either parent. In the reciprocal cross, the offspring are oversized and typically die before birth. Rare survivors are exclusively female, consistent with Haldane's rule, which states that in instances of hybrid sterility or inviability, the heterogametic sex tends to be more severely affected. To understand these sex- and parent-of-origin-specific patterns of overgrowth, we analysed reciprocal backcrosses. Our studies reveal that hybrid inviability is partially due to a maternally expressed X-linked PO locus and an imprinted paternally expressed autosomal BW locus. In addition, the hybrids display skewing of X-chromosome inactivation in favour of the expression of the BW X chromosome. The most severe overgrowth is accompanied by widespread relaxation of imprinting of mostly paternally expressed genes. Both genetic and epigenetic mechanisms underlie hybrid inviability in Peromyscus and hence have a role in the establishment and maintenance of reproductive isolation barriers in mammals.

Animals↗
PubMed1999

Intracellular trafficking and localization of the pseudorabies virus Us9 type II envelope protein to host and viral membranes.

The Us9 protein is a phosphorylated membrane protein present in the lipid envelope of pseudorabies virus (PRV) particles in a unique tail-anchored type II membrane topology. In this report, we demonstrate that the steady-state residence of the Us9 protein is in a cellular compartment in or near the trans-Golgi network (TGN). Through internalization assays with an enhanced green fluorescent protein epitope-tagged Us9 protein, we demonstrate that the maintenance of Us9 to the TGN region is a dynamic process involving retrieval of molecules from the cell surface. Deletion analysis of the cytoplasmic tail reveals that an acidic cluster containing putative phosphorylation sites is necessary for the recycling of Us9 from the plasma membrane. The absence of this cluster results in the relocalization of Us9 to the plasma membrane due to a defect in endocytosis. The acidic motif, however, does not contain signals needed to direct the incorporation of Us9 into viral envelopes. In this study, we also investigate the role of a dileucine endocytosis signal in the Us9 cytoplasmic tail in the recycling and retention of Us9 to the TGN region. Site-directed mutagenesis of the dileucine motif results in an increase in Us9 plasma membrane staining and a partial internalization defect.

Animals↗
PubMed1998

A gene-dosage PCR method for the detection of elastin gene deletions in patients with Williams syndrome.

Williams syndrome (WS) is a multisystem developmental disorder associated with microdeletions at 7q11.23 that involve several genes, including the elastin gene. Using genomic DNA from a panel of normal individuals and WS patients with established hemizygosity of the elastin gene locus, we have developed a quantitative polymerase chain reaction (PCR)-based gene-dosage assay that rapidly detects the loss of one allele of the elastin gene. Using this procedure, we also studied a family in which the proband was previously diagnosed with WS and her mother with a balanced 7q translocation [t(7:11)(q34;q13)]. Using DNA isolated from buccal smears obtained from several individuals in this family we were able to establish normal disomy at 7q in all family members except for the proband, in which we established hemizygosity at the elastin gene locus. We were also able to successfully infer normal disomy in an unborn child in this family. The rapid diagnostic procedure described here may have a variety of applications, including fine mapping of deletion breakpoints at 7q11.23 associated with WS.

Adult↗
PubMed1997

Effects of estrogen use on lens transmittance in postmenopausal women.

OBJECTIVE: Lens autofluorescence originates from an accumulation of fluorescent substances that are associated with the process of cataractogenesis and lens aging. The aim of this study was to determine whether postmenopausal estrogen use reduces age-related nuclear sclerosis in women. DESIGN: The authors designed a case-controlled study. PARTICIPANTS: Nineteen postmenopausal women reporting estrogen use for more than 4 years (group 1), 20 postmenopausal women reporting no estrogen use (group 2), and 23 age-matched men (group 3) were studied. INTERVENTION: The authors performed fluorophotometry. MAIN OUTCOME MEASURES: Corneal and lens autofluorescence and lens transmittance were measured. RESULTS: Lens transmittance values were 0.905 +/- 0.03, 0.839 +/- 0.08, and 0.841 +/- 0.08 in the three groups, respectively. There was a statistically significant difference between group 1 and the other two groups (P < 0.01). CONCLUSIONS: These data are suggestive of a protective effect of estrogen use on the lenses of postmenopausal women.

Aging↗
PubMed1996

Novel rhodopsin mutation in an autosomal dominant retinitis pigmentosa family: phenotypic variation in both heterozygote and homozygote Val137Met mutant patients.

A family affected with autosomal dominant retinitis pigmentosa (RP) is presented. Two clinically affected patients (mother and daughter) were heterozygous for the same novel missense mutation (Val137Met) of the rhodopsin gene (RHO). Both heterozygous and homozygous cases were observed among their few symptomatic relatives. Wide clinical variation was exhibited among the individuals with mutations in this family. None of the controls showed this change in RHO, nor has it been previously reported in other RP families. No other RHO mutation was observed. Additional genetic or environmental factors could play a role in modulating the penetrance and clinical expression of this RHO mutation.

Base Sequence↗
PubMed1992

Autosomal dominant retinitis pigmentosa (adRP): exclusion of a gene from three mapped loci provides evidence for the existence of a fourth locus.

Retinitis Pigmentosa (RP) is a group of inherited retinopathies which affect approximately 1 in 4,000 individuals. The disorder can be classified on the basis of inheritance; dominant, recessive and X-linked forms have been well documented. The existence of genetic heterogeneity within autosomal dominant RP (adRP) had been previously demonstrated. As a result of extensive linkage studies in 2 large Irish families and 1 American pedigree three adRP genes have been mapped. adRP genes have been localised to chromosome 3q close to the rod photoreceptor gene, rhodopsin; to chromosome 6p close to another transmembrane photoreceptor gene, peripherin/RDS and to the pericentric region of chromosome 8, although the causative gene in this region has not yet been identified. Here we report the results of a linkage study in a Spanish family, who exhibit an early-onset form of adRP. The adRP gene segregating in this family has been excluded from the three known adRP loci on chromosomes 3q, 6p and 8 using a series of both intragenic microsatellite markers from the rhodopsin and peripherin/RDS genes and markers flanking the three known loci. These results provide definitive evidence for the existence of a fourth adRP locus, further emphasising the genetic heterogeneity that exists within adRP.

Chromosome Mapping↗
PubMed1990

Naturally occurring cell death in the cerebral cortex of the rat and removal of dead cells by transitory phagocytes.

Regressive phenomena are common during the development of the nervous tissue. Among them, naturally occurring cell death has been observed in several regions of the nervous system. Cell death in the somatosensory cortex and medial cortical regions (hind limb, frontal cortex 1, frontal cortex 2, retrosplenial agranular, retrosplenial granular [Zilles K. et al. (1980) Anat. Embryol. 159, 335-360]) as well as in the cortical subplate (future subcortical white matter) in the rat mainly occurs during the first 10 days of postnatal life with peak values of 3.1 dead cells per 1000 live neurons at the end of the first week. Cell death progresses from birth to day 7 with a predominance of dead cells in the subplate and in layers II-III. Later, dead cells are more dispersed in the cerebral cortex, but a significant amount is still present in the subcortical white matter. This pattern correlates with the arrival and settlement of cortical afferents at the different cortical levels, as described in other studies, and points to the likelihood that transitory cellular populations are important clues in the modelling of the cerebral cortex during normal development. Transitory populations of macrophages (amoeboid or nascent microglial cells) that appear in great numbers during the same period and in the same regions are involved in the removal of dead cells.

Aging↗