Biomedical subjects

Michael Lynch

Publications and source records attributed to Michael Lynch.

59 records · Page 4Linked to original sources

PubMed2002

Transitional cell carcinoma metastatic to the eye in a collared peccary (Tayassu tajacu).

A 15-year-old female collared peccary (Tayassu tajacu) was presented for ophthalmic examination following sudden onset of blindness. Bilateral retinal detachment was diagnosed, neoplasia suspected, and euthanasia performed. Widespread tumor dissemination was apparent at autopsy, and transitional cell carcinoma was diagnosed histologically. The tumor was identified as arising from the ovary. Epidemiologic features of this case are discussed.

Animals↗

PubMed2002

Protocols, practices, and the reproduction of technique in molecular biology.

Protocols are one of the main organizational resources in molecular biology. They are written instructions that specify ingredients, equipment, and sequences of steps for making technical preparations. Some protocols are published in widely used manuals, while others are hand-written variants used by particular laboratories and individual technicians. It is widely understood, both in molecular biology and in social studies of science, that protocols do not describe exactly what practitioners do in the laboratory workplace. In social studies of science, the difference between protocols and the actual practices of doing them often is used to set up ironic contrasts between 'messy' laboratory practices and the appearance of technical order. Alternatively, in ethnomethodological studies of work, the difference is examined as a constitutive feature, both of the lived-work of doing technical projects, and of the administrative work of regulating and evaluating such projects. The present article takes its point of departure from ethnomethodology, and begins with a discussion of local problems with performing molecular biology protocols on specific occasions. The discussion then moves to particular cases in criminal law in which defense attorneys cross-examine forensic technicians and lab administrators. In these interrogations, the distinction between protocols and actual practices animates the dialogue and becomes consequential for judgments in the case at hand. The article concludes with a discussion of administrative science: the work of treating protocols and paper trails as proxies for actual 'scientific' practices.

Expert Testimony↗

PubMed2002

Spontaneous mutational variation for body size in Caenorhabditis elegans.

We measured the impact of new mutations on genetic variation for body size in two independent sets of C. elegans spontaneous mutation-accumulation (MA) lines, derived from the N2 strain, that had been maintained by selfing for 60 or 152 generations. The two sets of lines gave broadly consistent results. The change of among-line genetic variation between cryopreserved controls and the MA lines implied that broad sense heritability increased by 0.4% per generation. Overall, MA reduced mean body size by approximately 0.1% per generation. The genome-wide rate for mutations with detectable effects on size was estimated to be approximately 0.0025 per haploid genome per generation, and their mean effects were approximately 20%. The proportion of mutations that increase body size was estimated by maximum likelihood to be no more than 20%, suggesting that the amount of mutational variation available for selection for increased size could be quite small. This hypothesis was supported by an artificial selection experiment on adult body size, started from a single highly inbred N2 individual. We observed a strongly asymmetrical response to selection of a magnitude consistent with the input of mutational variance observed in the MA experiment.

Animals↗

PubMed2002

Links between community violence and the family system: evidence from children's feelings of relatedness and perceptions of parent behavior.

In this study, we examined some of the ways in which broader ecological systems may influence the organization of behavior within the family system. Specifically, links between exposure to community violence and children's relationships with maternal caregivers were investigated in a sample of 127 urban children between the ages of 7 and 13 years. Children were asked to indicate whether they had been exposed to a wide variety of violent events. In addition, their feelings of relatedness and separation anxiety, and their perceptions of maternal behavior were assessed. It was expected that exposure to community violence would be associated with feeling less secure with caregivers. Consistent with predictions from ecological-transactional theory, data supported this hypothesis. Children who reported that they had been exposed to high levels of community violence also indicated that they felt less positive affect when with their caregiver, were dissatisfied with how close they felt to her, felt more separation anxiety, and reported more negative maternal behavior than children exposed to less violence. Findings are discussed in terms of how violence may affect the family system and the protective function of human attachment.

Adolescent↗

PubMed2002

Hyperostotic bone disease in red pandas (Ailurus fulgens).

Three adult red pandas (Ailurus fulgens) developed multiple periarticular exostoses in their elbow joints. Two of these animals also had extensive periosteal new bone formation and osteosclerosis of the ulnae and radii and mild periosteal new bone deposition on the femurs. One animal also showed extensive hyperostosis of the cranium and mandibles. Dietary concentrations of calcium and phosphorus were estimated to be adequate, but dietary vitamin A and D appeared excessive when compared with recommended levels for this species. Serum vitamin A concentrations were not elevated in the two most severely affected animals, but their liver vitamin A content was higher than what is considered normal for most domestic animal species. Serum 25-hydroxy vitamin D concentrations were within normal ranges for domestic species. A definitive diagnosis for the cause of the lesions was not established, but hypervitaminosis A was suspected.

Animals↗