Search PubMed⌕ Search

Biomedical subjects

C Farrell

Publications and source records attributed to C Farrell.

At least 55 records · Page 3Linked to original sources
PubMed1984

Physical properties of the E. coli 4.5S RNA: first results suggest a hairpin helix of unusual thermal stability.

Hyperchromicity measurements and quasi-elastic laser light scattering (QELS) have been used to assess the solution structure of the metabolically stable E. coli 4.5S RNA. Results from thermal denaturation measurements revealed the 4.5S species to be markedly more stable than most other RNAs characterized thus far. Optical Tm's range from 79 degrees to 88 degrees with transitions approximately 25 degrees C wide. The Tm values show little dependence on ionic strength, but stability is enhanced considerably by Mg+2. In the QELS experiments the diffusion coefficient does not decrease until T greater than 70 degrees C. Neither the diffusive melting nor the diffusion coefficient at infinite dilution (D0(20,w)) show dependencies on ionic strength but both are influenced by Mg+2. The diffusion behavior is in agreement with that predicted for a rigid cylindrical molecule 125 to 160 A long and 37 to 26 A in diameter. Taken together these results are consistent with the more stable hypothetical secondary structures that can be formed, in which 70-75% of the 114 bases are paired to form a single extended hairpin helix.

Base Sequence↗
PubMed1984

The interaction of unregulated actin and myosin in avian muscular dystrophy.

The presence of an altered form of the heavy chain component of myosin subfragment-1 (S-1) in avian dystrophic pectoral muscle was confirmed by Triton-urea-acetic acid polyacrylamide gel electrophoresis. The potential functional significance of this altered form of S-1 was evaluated by measuring the ATPase activity of the unregulated acto-S-1 complex using all possible pairwise combinations of actin and S-1 from normal (N) and dystrophic (D) muscle. (NN, DD, ND, DN, where the first letter designates the actin and the second letter the S-1). With conventionally purified actin and S-1, NN not equal to DD not equal to ND not equal to DN, implying both N actin not equal to D actin and N S-1 not equal to D S-1 functionally. An alternate purification scheme for actin resulted in preparations from normal and dystrophic muscles of actin Mg-polymers with the same rheology (viscosity vs shear rate) and critical concentration for polymerization. When these actins were combined with more highly purified preparations of S-1, the adenosine triphosphatase (ATPase) activity of the acto-S-1 complex did not vary with changes in the pairwise composition and responded similarly to variation of the actin or adenosine triphosphate (ATP) concentration. In experiments with actin activation of intact myosin, no differences were observed between myosin from normal vs dystrophic muscle. The different isozymes of myosin present in normal and dystrophic chicken pectoral muscles are functionally equivalent as ATPases in their interactions with unregulated actin.

Actins↗
PubMed1981

Case report 158.

Explore the source record for details and available documents.

Chondrosarcoma↗
PubMed1980

Soluble immune complexes in cerebrospinal fluid of patients with multiple sclerosis and other neurological diseases.

The occurrence of soluble immune complexes (IC) in the cerebrospinal fluid (CSF) of 14 multiple sclerosis (MS) patients, four acute polyradiculoneuritis patients, 30 patients with other neurological diseases (OND) and 30 patients with disc prolapse (DP) was examined by a solid phase C1q-protein A binding assay (C1q-PABA) and a complement consumption test. IC-positive reactions were observed only in the C1q-PABA. The binding indices determined by the C1q-PABA differed significantly (P < 0.01) when the MS or the OND patient groups were compared to the DP group. No significant (P < 0.1) difference was observed between the indices in the MS and OND groups. Binding indices in C1q-PABA showed no correlation either to IgG concentration, total protein concentration or cell counts in CSF of MS patients. Three of the four polyradiculoneuritis patients were strongly IC-positive while the fourth patient was negative. Filtration and PEG-precipitation data indicated that a major part of the IgG-containing IC in CSF detected by C1q-PABA was of macromolecular nature.

Adolescent↗
PubMed1980

Determining growth rates of focal lesions of bone from radiographs.

Rate of growth divides focal lesions of bone into two classes which are largely mutually exclusive. Not all focal lesions require biopsy, and grading is especially helpful in deciding which should be biopsied and which may be safely followed. The statistical proof and logic of grading as an expression of growth rate are presented with a set of rules establishing each of the five grades in the presence of bone destruction. The radiologic signs necessary to establish rates are described and illustrated.

Bone Neoplasms↗
PubMed1980

Estimating rate of growth in bone lesions: observer performance and error.

In an experimental study of reader experience in identifying the variables essential to grading bone neoplasms, reader error is measured against book grade, a human consensus of the presence or absence of key variables. The average accuracy for classifying focal lesions into slow or fast categories is 83.4% for 890 readings as compared with average diagnostic accuracy of 53.7%. Analyses of human error have provided insight into how to improve the grading algorithm without significant loss of its ability to separate lesions into meaningful categories.

Bone Neoplasms↗
PubMed1979

Cancer of the breast. Mammography and thermography.

Quality mammography with knowledgeable interpretation is now a widely utilized and reliable procedure. It permits clinically occult lesions to be detected and clinically obvious or indeterminate lesions to be managed more intelligently. Abnormal mammographic signs are well defined, as are their differential diagnoses. Thermography of the breast is a younger science than mammography and must mature before its full potential can be realized. It is clear that thermography today cannot be considered an adequate prescreening technique to obviate further examination, as was once anticipated. Used in conjunction with physical examination and mammography it can serve to reinforce suspicions, and the high acceptability of the examination is an impetus to further clarify its role in detection.

Adult↗
PubMed1979

Cancer of the breast. Screening.

Screening is a more complicated issue than has been indicated in this chapter. Long-term followup is essential to exclude misleading initial impressions, and survival predictions must stand this test. The problem of interval cancers must be acknowledged, and methods of developing more cost-effective systems that might provide even broader coverage of the population at risk have to be considered. Suffice it to say that mass screening for breast cancer can be accomplished. Large numbers of American women are sufficiently concerned about this disease to participate, as evidenced by the success of the National Cancer Institute/American Cancer Society Breast Cancer Detection Demonstration Projects. It has been demonstrated that breast cancers so small that they would previously be considered a pathological curiosity are detected with surprising frequency. The ultimate effect on survival time by this screening can of course only be determined after passage of time, but there is every reason to believe that it represents one of the really great advances in detection-diagnosis in recent history. The chief detection modality is mammography, and it is to be expected that technological advances in this area will permit images of even greater reliability and resolution at a level of radiation exposure that will be acceptable to everyone. The definitive role of thermography in detection of breast disease has yet to be fully determined. The maximal scientific benefit and the true impact of the screening demonstration projects will be realized only after long-term followup of the 280,000 participants.

Adult↗
PubMed1977

A survey for circulating immune complexes in patients with acute myocardial infarction. Use of a C1q-binding assay with soluble protein A as indicator.

A new assay for the detection of circulating C1q-binding immune complexes (IC) is described. The assay makes use of solid-phase C1q and iodinated soluble protein A, extracted from the cell wall of Staphylococcus aureus. In a model system the assay could detect heat-aggregated IgG down to a concentration of about 50 ng/ml. This method and three other assays, previously described, were used to survey the appearance of IC activity in sera from hospitalized patients with acute myocardial infarction. Depending on the assay system used, from 56% to 66% of the patients investigated were found to develop circulating IC. The earliest appearance of circulating IC was noted 5 days after infarction. The highest incidence of positive reactions and the strongest reactions occurred 2 to 3 weeks after hospitalization; thereafter the IC positiveness tapered off, and all patients were negative 6 weeks after infarction.

Acute Disease↗