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Biomedical subjects

B Ericson

Publications and source records attributed to B Ericson.

8 recordsLinked to original sources
PubMed1999

Assessment of visual acuity in children aged 1 1/2-6 years, with normal and subnormal vision.

The aim of the study was to assess different visual acuity tests in the age group 1 1/2-6 years in 105 children with assumed normal vision, visual impairment due to ocular disease or strabismus. Acuity tasks for young children can be divided into three subtypes according to the kind of stimulus used. For "detection acuity", the stimulus should be detected or distinguished from the background, as assessed with the Stycar Rolling Balls. For "resolution acuity", the stimulus pattern should be resolved, as assessed with the Preferential Looking procedure (Teller Acuity Cards). For "recognition acuity", the stimulus must be recognized by the subject as assessed with the BUST-D symbol test, Sheridan Gardiner (S-G) single letters, LH single symbols and line tests, and also the HVOT test. Different acuity values were obtained with regard to detection, resolution and recognition acuities. Assessment with the Stycar Rolling Balls only gave a rough estimate of the visual function. There was an overestimation of the acuity values in all groups of children when using the Preferential Looking technique. Good agreement was found between the LH line and HVOT tests. The BUST-D test, S-G single letters, and LH single symbols gave slightly better acuity values than linear recognition tests. A "crowding ratio" was calculated by dividing the single optotype acuity by the linear acuity, and also by dividing the grating acuity by the optotype linear and single acuity. The crowding ratio varied in the individual children and in the different groups, being highest for strabismic amblyopia. The general conclusion is that reliable visual acuity measurements were not obtained until the visual acuity could be assessed with a recognition test using linear letters or symbols.

Adult↗
PubMed1997

Essential role of a kinesin-like protein in Arabidopsis trichome morphogenesis.

Little is known about how cell shape is controlled. We are using the morphogenesis of trichomes (plant hairs) on the plant Arabidopsis thaliana as a model to study how cell shape is controlled. Wild-type Arabidopsis trichomes are large, single epidermal cells with a stalk and three or four branches, whereas in zwichel (zwi) mutants the trichomes have a shortened stalk and only two branches. To further understand the role of the ZWI gene in trichome morphogenesis we have cloned the wild-type ZWICHEL (ZWI) gene by T-DNA tagging, and report here that it encodes a member of the kinesin superfamily of microtubule motor proteins. Kinesin proteins transport diverse cellular materials in a directional manner along microtubules. Kinesin-like proteins are characterized by a highly conserved "head" region that comprises the motor domain, and a nonconserved "tail" region that is thought to participate in recognition and binding of the appropriate cargo.

Acanthamoeba↗
PubMed1997

Map turtle winter leech loads.

Adult common map turtles, Graptemys geographica (n = 243), were obtained in November 1995 from a hibernation site in the Lamoille River, Vermont. Of the 208 female turtles examined, 151 (72.6%) had at least 1 leech (Placobdella parasitica) attached and 10 of 35 males (28.6%) were similarly parasitized. Mean abundances were 1.49 (SD = 1.461, n = 208) for female turtles and 0.34 (SD = 0.591, n = 35) for males; the difference was significant (t = 4.558, df = 241, P < 0.001). Leech broods were found on 34 of 208 female turtles (16.3%) and 2 of 35 males (5.7%). One of the leeches was of record size (77.7 mm total length); another specimen measuring 64.4 mm had 153 brood-sized (x = 4.5 mm) young attached to its venter. Because of poor visibility and partial ice cover, only 7 turtles were recovered in March 1996. All of these turtles had attached leeches, and 4 turtles had broods of 9-52 young ranging in length from 4.58 to 5.78 mm. One Placobdella ornata was found in the March sample. Our results suggest that leeches of various size classes remain attached to hibernating adult map turtles throughout the winter.

Animals↗
PubMed1987

Synthesis and immunogenicity of the rotavirus major capsid antigen using a baculovirus expression system.

Rotaviruses are the major pathogens that cause life-threatening diarrhea in young children and animals. We inserted a simian rotavirus SA11 gene 6 cDNA into the genome of the baculovirus Autographa californica nuclear polyhedrosis virus adjacent to the strong polyhedrin promoter. The major capsid antigen (VP6) was expressed in high yields (20 to 150 micrograms/10(6) cells) when Spodoptera frugiperda cells were infected with baculovirus recombinants containing SA11 gene 6 inserts. Reactivity with monospecific polyclonal and monoclonal antibodies suggested that VP6, expressed intracellularly or found in the media, maintained native antigenic determinants. VP6 purified from the media from infected cells also possessed a native oligomeric structure, was immunogenic in guinea pigs, and was able to spontaneously assemble into morphologic subunits. Antisera from immunized guinea pigs failed to neutralize virus in plaque reduction assays, but detected homologous and heterologous rotavirus strains when tested by immunofluorescence, immunoprecipitation, and enzyme-linked immunosorbent assays.

Antibodies, Viral↗
PubMed1985

Analyses of the mRNA transcription processes of snowshoe hare bunyavirus S and M RNA species.

The time course of synthesis of snowshoe hare bunyavirus small (S)- and medium (M)-sized viral RNA (vRNA), viral cRNA (vcRNA), and mRNA species was analyzed by using single-stranded DNA probes representing the S- and M-coded gene products. In the presence of puromycin, an inhibitor of protein synthesis, the subgenomic S mRNA species were detected, but not full-length S vcRNA or S vRNA species. No M-related RNA species were identified in puromycin-treated cells. In the absence of puromycin, full-length M and S vRNA, S vcRNA, and subgenomic S mRNA species were observed, as well as apparently full-length M vcRNA species, presumably including the approximately similar-sized M mRNA species. The 5' ends of the S and M mRNA species have been shown to be heterogeneous and some 12 to 17 bases longer than the ends of their corresponding presumptive replicative vcRNA species, in agreement with an earlier report that they represent nonviral primer sequences (D. H. L. Bishop, M. E. Gay, and Y. Matsuoko, Nucleic Acids Res. 11:6409-6418, 1983). The 3' ends of the M and S mRNA species were found to be shorter by some 60 and 100 nucleotides, respectively, than those of their corresponding full-length vcRNA species. Comparison of the 3' noncoding regions of the S and M vcRNA species revealed that there are conserved sequences following the translation termination codons of the two RNA species. One of these conserved sequences is a pyrimidine-rich template sequence that is approximately 20 nucleotides beyond the deduced S mRNA transcription termination site.

Base Sequence↗
PubMedDate not supplied

Assessing visual function in children younger than 1 1/2 years with normal and subnormal vision: evaluation of methods.

PURPOSE: Methods for detecting subnormal vision early in life are needed to adequately diagnose the condition and begin treatment and rehabilitation. METHODS: Forty-six children ages 1 month to 1 1/2 years with either assumed normal vision, visual impairment due to eye disease, or strabismus were examined with the following tests: Stycar rolling balls; preferential looking (Teller acuity cards); and the ability to detect raisins, puffed rice, and sugar strands on two different backgrounds, one white and one black. RESULTS: Children with visual impairment and strabismus often showed normal values for their age, and children with assumed normal vision sometimes had values below those established for normal development of vision with the Stycar rolling balls and the Teller acuity cards. CONCLUSIONS: It is not possible to use these tests to reliably differentiate among normal vision, visual impairment, or strabismus in children younger than 1 1/2. Not until recognition acuity, symbols, or letters can be tested can reliable results be obtained. However, the tests are useful to estimate the general visual function of children in this age group.

Contrast Sensitivity↗