Biomedical subjects

E G Williams

Publications and source records attributed to E G Williams.

12 recordsLinked to original sources

PubMed1992

Techniques for clearing ovules for studies of megagametophyte and early postfertilization development in Rhododendron.

Using ovule clearing, more than 33,600 ovules of Rhododendron nuttallii T. W. Booth (Ericaceae) were examined for megagametophyte and early postfertilization stages at daily intervals from anthesis until 3 weeks after pollination. Pretreatments with amyloglucosidase to digest integumentary and gametophyte starch and Stockwell's bleach to remove tannins from the integumentary epidermis were necessary. Ovules were cleared by a combination or modifications of Herr's four-and-a-half or Stelly's hemalum-methyl salicylate techniques and were observed using differential interference contrast optics. The method proved suitable for large-scale quantitative studies of ovule development and fertilization. A general protocol is suggested as a starting point for ovule clearing studies.

Fertilization↗

PubMed1991

Vocal cord paralysis in the Shy-Drager syndrome. A cause of postoperative respiratory obstruction.

A case is presented in which unexpected and persistent postoperative respiratory problems led to the finding of bilateral abductor vocal cord paralysis and confirmed the diagnosis of the Shy-Drager syndrome. Anaesthetists should be aware that vocal cord paralysis may be a feature of this uncommon condition, and should consider the possibility of glottic obstruction as a cause of ventilatory difficulties.

Humans↗

PubMed1986

A rocking table for staining electrophoretic gels, nitrocellulose blots and histological slides.

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Electrophoresis, Polyacrylamide Gel↗

PubMed1985

Applications of fluorochromes to pollen biology. II. The DNA probes ethidium bromide and Hoechst 33258 in conjunction with the callose-specific aniline blue fluorochrome.

Techniques are described for detection of pollen grain and pollen tube nuclei using the fluorescent DNA probes ethidium bromide or Hoechst 33258, in conjunction with the aniline blue fluorochrome sirofluor, which stains the callose component of pollen tube walls and plugs. The DNA probes, which may be used either as vital stains or following fixation, permit discrimination between vegetative and generative or sperm nuclei. Double staining with sirofluor allows location of nuclei within pollen tubes grown in vitro, and when used after pollination enables the viewer to discriminate between nuclei within the pollen tube vs. nuclei of the pistil tissue.

Benzenesulfonates↗

PubMed1984

Post-pollination callose development in ovules of Rhododendron and Ledum (Ericaceae): zygote special wall.

In Rhododendron spp. and Ledum groenlandicum a callose wall is laid down around the zygote in the first 2 days after fertilization. The periodic acid/Schiff-positive, aniline blue-fluorescence-positive callosic wall is initiated adjacent to the degenerating synergid, extends to cover the entire zygote surface, and remains visible during the initiation of embryogeny as the zygote elongates before the first proembryonal division. Unfertilized ovules show eventual callose deposition in the ovule wall cells during senescence in undeveloped abscising pistils, but show no development of callose within the embryo sac. Possible roles of a zygote special callose wall are discussed.

Cell Wall↗

PubMed1983

Adolescent loneliness.

The purpose of this study was to investigate the phenomenon of loneliness in delinquent adolescents with regard to types of delinquency offenses committed, demographic characteristics, and personality characteristics in the areas of interpersonal needs for inclusion, control, and affection. The types of delinquency offenses were categorized as burglary, runaway, drugs, assault, and incorrigible. The demographic variables examined were age, sex, race, family rank or birth order, family structure in terms of parental presence, family income level, religion, and geographic locale. A sample of 98 adolescents was obtained from juvenile detention facilities in three metropolitan areas in the United States. Subjects ranged in age from 12 to 18. Subjects were asked to complete the Loneliness Questionnaire as a self-reported measure of loneliness. Subjects also provided information about themselves relative to demographic characteristics and completed the FIRO-B Questionnaire, which measured interpersonal needs for inclusion, control, and affection. The results revealed no significant differences with regard to any of the demographic variables when the effect of each was considered alone. However, there was a significant effect on loneliness by income when considered jointly with other demographic variables. Adolescents from the middle income group expressed more loneliness than those from the upper and lower income groups. No significant differences were observed with regard to personality characteristics related to interpersonal needs for inclusion and affection, but delinquent adolescents with medium to high needs for control indicated significantly more feelings of loneliness than delinquent adolescents with low needs for control.

Adolescent↗

PubMed1973