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Biomedical subjects

P W Martin

Publications and source records attributed to P W Martin.

11 recordsLinked to original sources
PubMed1988

Respiratory cryptosporidiosis in chickens.

In order to better characterize spontaneous respiratory cryptosporidiosis in chickens, a retrospective examination of histopathology reports from the Georgia Poultry Laboratories for an 18-mo period (4/1/86 to 9/30/87) was made; 12 cases were found. Collected data were analyzed and certain epidemiologic and histologic features were identified. Eleven of the 12 cases involved broiler type chickens. The ages of chickens with respiratory cryptosporidiosis were evenly distributed between 17 and 52 days of age. The infected birds were always clinically ill. Viruses or bacteria or both often accompanied respiratory Cryptosporidium sp. infections. Histologic lesions (including those of ciliary-adherent bacteria) are described. As the inflammatory response in infected organs became progressively nonpurulent (lymphocytes and plasma cells predominate), numbers of Cryptosporidium diminished. Cytologic preparations were useful for making diagnoses of respiratory cryptosporidiosis in chickens. Identification of epidemiologic features of respiratory cryptosporidiosis, and improved ability to make accurate and prompt diagnoses of Cryptosporidium sp. infection, are vital for a more complete understanding of the impact of this disease on poultry health.

Animals↗
PubMed1984

Perturbed gamma-gamma angular correlation studies of 111In bound to double and single stranded DNA.

Using 111In as a probe, the dynamics of double and single stranded DNA have been studied by performing time-differential gamma-gamma angular correlation measurements on the 173-247 keV transitions in 111Cd. Binding of indium to DNA was investigated by analysis of sedimentation profiles, thermal transition spectrophotometry and electrochromatography. Rotational correlation times tau c greater than or equal to 400 ns and tau c = 27 +/- 7 ns were obtained respectively for double stranded (native) and single stranded (denatured) DNA. The corresponding quadrupole interaction frequencies were omega 0 = 711 +/- 15 Mrad/s and omega 0 = 151 +/- 13 Mrad/s.

DNA↗
PubMed1982

Evaluating alternative techniques of questioning mentally retarded persons.

In an examination of methodological issues involved in interviewing retarded persons, alternatively worded or structured questions were embedded in interviews with three samples. Questioning techniques were evaluated according to the extent to which (a) interviewees could provide answers, (b) their answers agreed with parallel responses given by attendants or parents, and (c) answers were free of systematic response bias. Open-ended questions were found to be unanswerable by many persons, and supplementing them with clarifying examples and probes for additional information only exacerbated response bias. By comparison, yes-no checklists enhanced responsiveness but introduced serious acquiescence bias, whereas multiple choice questions, particularly with pictures, yielded valid answers from high proportions of interviewees. Implications for question design were discussed.

Adolescent↗
PubMed1980

Surveying mentally retarded persons: responsiveness and response validity in three samples.

In an exploration of the feasibility and utility of survey research with retarded populations, interviews were conducted with 52 institutionalized children, 58 institutionalized adults, and 57 community children, as well as with their parents or attendants. Analyses indicated that higher IQ interviewees were generally more responsive to questions, more often in agreement with the nonretarded informants, and less acquiescent on yes-no questions than were lower IQ interviewees. Although these relationships varied in strength from sample to sample, overall differences among samples were nonsignificant. Implications for researchers interviewing retarded persons were discussed.

Adolescent↗
PubMed1978

In-111 transferrin labeling studied by perturbed angular correlations.

The technique of perturbed angular correlations (P.A.C.) was used to study transferrin labeled with radioactive indium. Three forms of the labeled system were studied: a) the In-111 was bound to transferrin with no iron present at either of the binding sites; b) the In-111 probe was used to label transferrin that was 33% saturated with iron; and c) the label was attached to saturated Fe-transferrin. The measured perturbation factors, G22(t), indicate that the three binding states are clearly differentiated. Cases (a) and (b) exhibit characteristic features of time-independent quadrupole interactions and the average quadrupole interaction frequencies, omegaq, were determined in these cases.

Binding Sites↗