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Biomedical subjects

J M Reid

Publications and source records attributed to J M Reid.

At least 91 records · Page 5Linked to original sources
PubMed1986

Multifrequency holography using backpropagation.

The technique of wavefield backpropagation has been used quite extensively in the literature. We report on an analytical study of the resolution properties of this technique. Backpropagation as a form of holographic reconstruction suffers from poor axial resolution. We derive expressions for both the axial and the lateral resolutions. We also show that the axial resolution can be substantially improved by the use of multiple frequencies. We derive an expression relating the resolution and bandwidth.

Fourier Analysis↗
PubMed1984

Epidemiological and other studies in the assessment of factors contributing to cataractogenesis.

Some problems of cataract epidemiology are briefly reviewed. Studies of the incidence and prevalence of cataract, and of economic status, measure social need but cannot, by themselves, point to possible causes. Information on geographical or regional distributions and medical, clinical and occupational studies permit the formulation of socially, medically or experimentally testable hypotheses concerning specific contributory factors. We have found several such factors to be significantly associated with cataract; they appear to be risk factors. Some risk factors are associated with subclinical deviations from the range of normal concentrations of certain plasma constituents, whereas clinically or experimentally acute deviations are known to be rapidly cataractogenic. Other risk factors include medical conditions and certain drugs. Although individuals may have several risk factors, controls have significantly fewer than cataract patients of the same age. This difference in the number of risk factors is also age-related, as is the degree of divergence from the normal range in the concentrations of several plasma constituents.

Aged↗
PubMed1982

Morbid obesity.

Explore the source record for details and available documents.

Adult↗
PubMed1982

Complete congenital heart block. Report of 35 cases.

Congenital complete atrioventricular block is uncommon, and the outlook is usually regarded as favourable. Thirty-five patients with congenital heart block are presented. There was no obvious sex difference and their ages ranged from 12 days to 85 years, though most were under the age of 20 years when first seen. Accompanying heart disease was noted in six, but presentation with symptoms in early infancy was a more serious risk factor in our experience. Permanent pacing was required in 21, three of whom were neonates. One of the 14 unpaced patients died unexpectedly at the age of 5 years. Long term supervision is necessary, as most will require permanent pacing before their 50th birthday.

Adolescent↗
PubMed1982

The management of congenital aortic stenosis.

The progress of 128 patients with congenital aortic stenosis has been followed from one to 28 (mean 14) years. Fifty-eight underwent cardiac catheterisation, and 46 (36% of the total) required surgical treatment. Of these, 42 were under 20 years old. Additional cardiac lesions were noted in five. Infective endocarditis was encountered in four. The onset of symptoms or increasing evidence of left ventricular hypertrophy on the electrocardiogram were the principal indications for catheterisation. Two-dimensional echocardiography is now important in this context. There were four deaths in the 46 surgically treated patients; three of these were early and the fourth was a late death three years after operation due to a massive cerebral embolus complicating infective endocarditis. The 42 survivors of operation and the 82 unoperated patients have remained under long-term supervision. Further surgery was necessary in 12 of the 42 surgically treated patients--valve replacement in seven of them two to eight years after valvotomy, replacement of a calcified xenograft valve in three, and repeat operation in two because of recurrence of subvalvar obstruction. Aortic stenosis is not a benign condition in childhood and adolescence. Close supervision is necessary and when any deterioration is detected further investigation as a prelude to probable surgery is mandatory. This should not be embarked on lightly in childhood unless there are pressing indications, particularly in view of the serious disadvantages of valve replacement in childhood.

Adolescent↗
PubMed1982

Some risk factors associated with cataract in S.E. Scotland: a pilot study.

Problems of epidemiological studies of cataract are outlined. Some results are reported from a study on 931 cataract patients and 325 non-cataractous individuals. After correction by age and sex several single variables were found to have significant positive or negative correlations with cataract. Interactions between variables were found; these include age, diabetes, the use of diuretics and cataract, between age, sex, the level of alcohol consumption and cataract, and between age, sex, plasma urea levels and the use of different diuretic drugs, only some of which were found to have a positive association with cataract.

Aged↗
PubMed1981

Quantitative acoustical assessment of wound maturation with acoustic microscopy.

Preliminary results of the ultrasonic characterization of cutaneous wound tissue and surrounding margin, obtained with the scanning laser acoustic microscope, show an increase in the speed of sound and in the acoustic heterogeneity as function of wound age. As the wound age increased, the following results were noted: (1) The wound area, initially quite homogeneous in acoustic appearance, became more heterogeneous; (2) the acoustic appearance of the wound tended to become similar to that of the adjacent tissue; and (3) the ultrasonic velocity of the wound area increased from a range of 1540--1575 m/s at 7 days to a range of 1700--2000 m/s at 35 days.

Animals↗
PubMed1979

Polymyositis and complete heart block.

The development of complete heart block is described in a patient with polymyositis. The implantation of a permanent pacemaker has controlled the heart block, but the progression of the underlying disease despite treatment with relatively high dosage of corticosteroids makes the outlook uncertain.

Adult↗
PubMed1979

Pulmonary hypertension accompanying ventricular septal defect and patent ductus arteriosus. Management in infancy and early childhood.

Forty-one infants and children with the combination of patent ductus arteriosus (PDA) and ventricular septal defect (VSD) were encountered over 20 years. Twenty-four presented in infancy with congestive cardiac failure. Pulmonary hypertension was present in 32, the cause in 19 being increased pulmonary blood flow. Increased pulmonary vascular resistance (PVR) was detected in 13 (indicated by a pulmonary to systemic resistance ratio (Rp : RS) greater than 0.24:1 and PVR greater than 4 units). Thus 22% had a pulmonary artery systolic pressure less than 30 mmHg and 68% had a pulmonary vascular resistance below four units, indicating an unusually mild form of the combined condition in these patients. Surgical management is discussed, and in particular the question of simultaneous closure of the defects during infancy. Cardiac failure, resistant to drug treatment, and increased PVR are indications of operation. The PDA should be closed and only if there is no substantial fall in pulmonary artery pressure is the VSD repaired.

Child↗
PubMed1979

Trustee development comes of age.

Cursory and sporadic attempts to educate trustees are giving way in many hospitals to systematic programs of board development, encompassing traditional facility orientation, continuing education and information programs, and other efforts to contribute to improved board performance. This article suggests steps for boards to follow in launching a board development program: vehicles for board development: and the composition and responsibilities of the board development committee.

Education↗