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Biomedical subjects

R Barnes

Publications and source records attributed to R Barnes.

At least 145 records · Page 8Linked to original sources
PubMed1976

Failure to suppress theta antigenic expression in progeny derived from pre-immunized maternal recipients.

One possible theory concerning the success of the fetus as an allograft has been attributed to maternal modification of foreign fetal antigenic expression. In this respect progeny derived from pre-immunized maternal mouse recipients, have been examined for any modification (reduction) of corresponding theta antigen determinants. Two major groups of mice were examined. The first group of embryo transplantation derived AKR homozygotes born from pre-immunized CBA recipients whilst producing the corresponding anti-thetaAKR antibody activity. The second group of naturally derived reciprocal (CBA x AKR)F1 heterozygotes were also born from pre-immunized maternal recipients. In neither group was theta expression found to be modified and the significance of this finding is discussed in respect of other situations where fetal antigenic expression is known to be altered by maternal influence.

Animals↗
PubMed1976

Subcapital fractures of the femur. A prospective review.

This abridged account of a report to the British Medical Research Council describes a long-term investigation of 1,503 subcapital fractures of the femur, almost all of which were treated by reduction and internal fixation. With three exceptions, union occurred in all Garden Stage I and Stage II fractures and in 67% of Stage III and Stage IV fractures, of which only 14-5% were united at six months. In women, late segmental collapse was seen after union had occurred in 16% of Stage I and in 27-6% of Stage III and Stage IV fractures. Delay of up to one week before operation had no significant effect on the incidence of non-union or of late segmental collapse. The incidence of union followed by late segmental collapse was higher in women with normal bone density than in those with osteoporosis. Smith-Petersen nailing was found to be the least effective form of fixation in displaced fractures. The age and physical state of the patient, the accuracy of reduction, and the security of fixation had the greatest influence on union.

Age Factors↗
PubMed1975

A family with an unusual occupational hazard.

Pneumoconiosis from the carbon-copper-silica rods of film projector arc lamps is a relatively rare disease. There follows a description of a family in which the father and two sons developed radiographic changes after many years working as projectionists in New South Wales.

Aged↗
PubMed1975

Echocardiography in evaluation of mitral valve prostheses.

Thirty-three patients with mitral valve prostheses were studied with echocardiography in an effort to determine if this technique could be useful in detecting significant abnormalities. Recordings were obtained in the supine position with the transducer directed to record maximum excursion of the prosthesis. Echoes from the struts, poppet and sewing ring were readily recorded. Amplitude of excursion and opening and closing velocities of the poppet were measured. Fifty echocardiographic recordings were obtained from the 33 patients. Of the 33 patients studied, 22 were thought to have "normal" echo tracings while in 11, the tracings were considered "abnormal." Apparent abnormalities consisted of: 1) abnormal diastolic separation between the poppet and strut, 2) increased echoes near the poppet, strut or sewing ring and 3) a combination of both. There was only one instance of suspected "sticking" of the prosthesis. All patients who had "abnormal" studies except one developed complications associated with their prosthesis (90%) compared to only 36% in patients with "normal" tracings. Five patients in each group died. Autopsy studies are described and correlations with the echocardiographic findings are made. In low profile valves reduction in excursion of the disc may be an indication of malfunction. Echocardiography appears to be of value in the assessment of function of mitral valve prostheses.

Adolescent↗
PubMed1975

The relation between sub-capital fracture of the femur and mineral content of the right third metacarpal.

Positive correlation between the mineral content of the mid site of right third metacarpal and neck of femur has been established using the psi-ray absorption technique described by Shimmins et al. (1972b) to make measurements on excised human bones. An X-ray method (Anderson, Shimmins and Smith, 1966; Shimmins et al. 1972a) was used to measure the mineral content of the right third metacarpal in 101 female and 22 male patients with subcapital fracture of the ferum. When their metacarpal "whole bone densities" were compared with those of control subjects of the same age and sex, they were found to have significantly lower (P smaller than (0.025) average values. However, groups of patients defined according to Garden's classification of severity of fracture could not be distinguished one from the other on the basis of metacarpal whole bone density measurement.

Adult↗
PubMed1975

Sutures and bladder wound healing in the experimental animal.

An incision was made in the bladder of each of 81 female rats, then closed with various types and sizes of sutures and by different methods in order to determine the optimum suture and method to facilitate watertight closure and wound healing. Chromic catgut, collagen, and polyglycolic acid sutures, of different sizes, were used. Pressure studies and microscopic examinations of the wound were done at different intervals. All sutures lasted long enough to allow healing of the wound and none broke during pressure studies. A two-layer continuous closure with fine suture was the most watertight. Tissue reaction was almost absent when polyglycolic acid suture was used and was minimal with fine chromic catgut.

Absorption↗
PubMed1975

New systems for a two-speed electroencephalograph with an auditory device for diminishing the length of seizures.

The author describes a system for testing patients with petit mal seizures. The system has the following advantages: 1) EEG paper speed is automatically increased from 2.5 mm/s to 25 mm/s when brainwave activity increases, with the increased speed maintainable for up to 4.0 sec after the last seizure burst. Control studies with constant speed and two-speed systems operating simultaneously demonstrate that no significant distortion occurs at the moment of change in speed. The convenience of handling a greatly reduced volume of paper is obvious. 2) An auditory stimulus, either a pure tone burst of 1000 HZ or loud music, is also triggered by an increase in amplitude of brainwave activity. Testing of 15 patients shows a significant decrease (p less than 0.01) in duration of seizure activity when the stimulus is activated.

Acoustic Stimulation↗
PubMed1974

[Rooming-in].

Explore the source record for details and available documents.

Female↗
PubMed1973

A bacteriological evaluation of laminar-flow systems for orthopaedic surgery.

An evaluation has been undertaken of the efficiency of laminar-flow ventilation in operating-rooms in which conventional operating-room clothing was used. It has been demonstrated that velocities in the region of 0.3-0.4 m./sec. will give maximum returns for effort in both down-flow and cross-flow systems. At this velocity the laminar-flow system, in terms of airborne bacteria measured at the wound site, was about 11 times more efficient using horizontal air-flow and 35-90 times more efficient using vertical air-flow than a plenum-ventilated operating-room.

Air Conditioning↗
PubMed1973

The electron-transport system of mitochondria from the slime mould Physarum polycephalum.

A method is described for the preparation of mitochondria from the slime mould Physarum polycephalum; the mitochondria were not coupled. P. polycephalum mitochondria oxidized added NADH via a rotenone-insensitive pathway, but the oxidation of malate plus glutamate was rotenone sensitive; both of these substrates reduced much less cytochrome b than did succinate, in both aerobic and anaerobic steady states. Spectroscopy at 77 degrees K separated three absorption maxima in the alpha-band region, at 560nm, 553nm and one at 547nm due to cytochrome c. The absorption at 553nm was increased in the aerobic steady state by the addition of 2-heptyl-4-hydroxyquinoline N-oxide, suggesting that it was due to a b-type cytochrome. All three absorption maxima appeared in the aerobic steady state after the addition of a range of substrates. The respiratory activity with different substrates and the response to inhibitors of respiration were similar to those previously described for fungus mitochondria (Weiss et al., 1970; Erickson & Ashworth, 1969). When grown under conditions of haem limitation the mitochondria contained a lower concentration of cytochromes than normal.

Adenosine Triphosphate↗