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Biomedical subjects

G R Smith

Publications and source records attributed to G R Smith.

At least 307 records · Page 17Linked to original sources
PubMed1978

Pattern discrimination in matching chest radiographs. Including a role for logistic distribution of observer responses.

Tests were designed to determine how well individuals can differentiate similar chest radiographs. These tests were given to 17 persons (radiologists, x-ray technologists, medical students, and secretaries). Each test contained a number of paired, dissimilar, and/or unique radiographs which were to be distinguished from one another or matched. The results suggest, that a radiologist does not have an innate advantage over untrained observers in pattern recognition. It is not known whether pattern-recognition tests are valuable in evaluating potential radiologists. A receiver operating characteristic curve is also described.

Diagnostic Errors↗
PubMed1978

Somatomedin bioactivity in serum and amniotic fluid during pregnancy.

Somatomedin bioactivity (SMA) in maternal serum, as measured by hypophysectomized rat cartilage assays, was low during early and late pregnancy but was similar to normal nonpregnant control levels near 28 weeks and at term pregnancy. At term, the mean level of SMA in cord serum was significantly less than in maternal serum, and greater than in amniotic fluid. The mean level of SMA in amniotic fluid was higher at term than in early pregnancy. No significant correlation was noted between SMA levels in amniotic fluid, maternal serum or cord serum, or between the SMA levels in these samples and the usual amniotic fluid parameters used as indices of fetal maturity.

Amniotic Fluid↗
PubMed1977

Avian botulism and the high prevalence of Clostridium botulinum in the Norflok Broads.

An account is given of a severe outbreak of type C botulism in waterfowl that occurred on the Norfolk Broads during the exceptionally warm summer of 1975. Forty-five mud samples were collected from 22 well distributed aquatic sites representing a considerable proportion of the total number of Broads. All samples except one (ie, 97-8 per cent) were shown to contain Clostridium botulinum and 58 per cent contained more than one type of the organism. Types B, C and E were demonstrated in 62-2 per cent, 51-1 per cent and 60 per cent of samples respectively. Recent surveys, made by identical methods, of aquatic environments in the London area and the Camargue (France) showed prevalences of Cl botulinum of 72-5 per cent and 4-5 per cent respectively. It seems likely that the Norfolk Broads will continue to present a risk to waterfowl from botulism in future hot summers.

Animals↗
PubMed1977

Anatomical variations in the articular masses of the seventh cervical vertebra simulating fracture.

The articular masses of the seventh cervical vertebra are variable in that about 87% of patients the superior and inferior facets are not parallel. IN ADDITION, THE INFERIOR FACETS ARE OFTEN POSTERIORLY PLACED IN RELATION TO THE SUPERIOR FACETS. These factors contribute to a notched undulating articular mass seen bilaterally on the lateral and oblique projections simulating fracture. The difference in inclination of the superior and inferior facets may cause either the superior or inferior facets to be obscured on the AP VIEW ANGLED CAUDAD--THE POSTERIOR ARCH VIEW. Since these anomalies are bilateral and fractures are almost always unilateral, the differentiation is most easily made on this posterior arch view.

Cervical Vertebrae↗
PubMed1977

The low prevalence of Clostridium botulinum in the lakes, marshes and waterways of the Camargue.

Mud samples collected in June 1975 from the lakes, marshes and waterways of the Camargue were examined for Clostridium botulinum. The Grand Rhône and Petit Rhône were shown to contain types B and E, but of 44 samples taken from well distributed sites on the Ile de la Carmargue, only two (4-5%) were positive and these contained type E alone. The survey indicated a much lower prevalence of Cl. botulinum than any encountered in recent surveys of inland aquatic environments elsewhere.

Clostridium botulinum↗
PubMed1977

A comparison of the distribution of Clostridium botulinum in soil and in lake mud.

In 1975, 25 soil samples were collected from the London area. Of these, 20 were obtained 200-300 yards from 20 lakes that had been shown in 1974 to contain mud contaminated with one or more of types of B, C, D, and E of clostridium botulinum. By means of a technique comparable with that use for the examination of mud, the 20 soil samples were found negative. The remaining 5 soil samples, obtained from sites that were not in close proximity to lakes, were also negative except for one that contained type B.

Clostridium botulinum↗
PubMed1977

Jumpers' fractures: patterns of thoracolumbar spine injuries associated with vertical plunges.

Thirty-eight patients who fractured the dorsolumbar spine by vertical plunges are evaluated. The patterns and classification of fractures in cases is presented as well as their salient clinical features. The role of the radiologist in the care of acute spine injuries is highlighted based on the therapeutic implications of proper fracture classification. The role of body section radiography in evaluating patterns of posterior element fractures is suggested.

Adult↗
PubMed1977

Observations on the possible invasiveness of Clostridium botulinum for waterfowl.

Twenty-four ducklings given multiple doses of Clostridium botulinum type C spores and toxin per os and 27 affected waterfowl from four natural outbreaks of the disease were examined bacteriologically. No evidence of invasion of the blood or liver was found in any bird and it is suggested that invasiveness and toxigenesis in internal organs are probably of little, if any, importance in the causation of botulism in waterfowl.

Animals↗
PubMed1977

Inhibition of the growth of some strains of Mycoplasma mycoides subsp mycoides by the blood of certain horses.

When incorporated in solid medium at a concentration of 15 per cent, the defibrinated blood of certain horses strongly suppressed the growth of some, but not all, strains of Mycoplasma mycoides subsp mycoides so that many colonies failed to develop to a visible size. Blood from a single rabbit was tested and found to exert a similar effect. There was striking variation in the degree of inhibition produced by different samples of horse blood and, of five strains of the organism examined, the T1 vaccine strain was the most susceptible. The results suggested that the effect was not due to antibody.

Animals↗
PubMed1976

Articular mass fracture: a neglected cause of post-traumatic neck pain?

Fifty-one compressed distorted cervical articular masses were found in 29 patients seen at this institution over a nine-month period. The significance of these findings is discussed and it is concluded that in most instances these represented compression fractures with deformity of the articular process. Selected signs suggestive of a compressed articular mass are identified on various views. These include (1) neuroforaminal encroachment or narrowing, (2) triangular appearance of the lateral mass in the oblique view, (3) unilateral anterior displacement of the superior facet with respect to the inferior facet, (4) minor anterior subluxation of one vertebral body over another, (5) double outline sign on the lateral view, (6) abnormally visible posterior articulations on the routine AP view. The articular processes are best shown on anteroposterior angled caudad views and lateral tomography. Articular mass deformity frequently appears to be associated with persistent post-traumatic neck pain and a relationship between this deformity and primary or secondary degenerative cervical disc and joint disease is suggested.

Adult↗
PubMed1976

Deletions of lambda phage locating a prm mutation within the rightward operator.

Two deletion-substitution mutations of phage lambda, spi-113 and spi-274, are shown to remove about half of the rightward operator OR. Physiological studies show that spi-113 is still repressible. Thus, the 50 or so nucleotides of OR deleted in this mutant are not absolutely essential for repression. prm-116, which inactivates the promoter essential for the maintenance of lambda repressor synthesis, is located within OR between the endpoints of spi-113 and spi-274.

Base Sequence↗
PubMed1976

Stab wound causing mesenteric-portal arteriovenous fistula: an unusual case with a spontaneous closure.

A case of spontaneous closure of a mesenteric-portal arteriovenous fistula secondary to a stab wound is described. Although a variety of clinical complications can result from such fistulae, it is not always possible to perform an immediate closure of such lesions. The patient described was unable because of his condition to undergo surgical repair of his fistula: when readmitted after 2 months the fistula had closed and the artery was normal.

Adult↗
PubMed1976

A simple method of femorocerebral catheterization.

A method of catheterizing the cerebral vessels by the femoral route which does not require seating the end hole prior to guide wire introduction has been devised. The orifice of the desired vessel can be localized fluoroscopically via contrast material injections without undue manipulation prior to guide wire introduction.

Catheterization↗
PubMed1976

Radiologic classification of posterior dislocations of the hip: refinements and pitfalls.

Seventeen traumatic hip dislocations seen during a 15-month period were evaluated. In 10 of the 14 cases of posterior hip dislocation, the final Thompson-Epstein classification differed from the initial radiographic classification. Dislocations of the hip often result in radiographically obscure femoral head and acetabular damage. High quality radiographs with oblique and coned-down views are of substantial aid in evaluating the dislocated hip. After closed reduction of a dislocated hip, further views and tomography are helpful but diagnostic pitfalls exist. A persistently widened hip joint, even with negative plain films and tomography, indicates possible intra-osteochondral debris or incompletely reduced femoral head fragments.

Adolescent↗