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Biomedical subjects

S G Edwards

Publications and source records attributed to S G Edwards.

25 records · Page 2Linked to original sources
PubMed2000

Selective medium based on tyrosine metabolism for the isolation and enumeration of Brevibacillus brevis (Bacillus brevis).

AIMS: To develop a selective medium for the enumeration of Brevibacillus brevis Nagano spores from soil and plant material. METHODS AND RESULTS: Tyrosine agar was developed as a selective medium and compared with nutrient agar for the enumeration of B. brevis Nagano spores from sterile and non-sterile plant and soil extracts. Brevibacillus brevis Nagano colonies could be easily identified only on tyrosine agar due to their clear halo and distinct colony morphology. Identification was confirmed by thin layer chromatography of the antibiotic, gramicidin S, produced by this strain. CONCLUSIONS: Tyrosine agar was shown to be a suitable selective medium for the enumeration of B. brevis Nagano. SIGNIFICANCE AND IMPACT OF THE STUDY: The medium developed, tyrosine agar, can be used to monitor the population of the biological control agent, B. brevis Nagano, and will allow detailed studies within the crop environment.

Bacillus↗
PubMed2000

Nonoperative treatment of ipsilateral fractures of the scapula and clavicle.

BACKGROUND: Internal fixation of one or both bones is the recommended treatment for floating shoulder injuries (ipsilateral fractures of the scapula and clavicle). Perceived risks of nonoperative treatment include abduction weakness, decreased range of motion, chronic pain, malunion, and nonunion. None of these problems, however, have been confirmed by clinical studies. The purpose of this retrospective study was to analyze the clinical and radiographic results of nonoperative treatment of floating shoulder injuries. METHODS: Twenty patients with a floating shoulder injury were treated with either a sling or a shoulder immobilizer. Eleven clavicular fractures were displaced ten millimeters or more, and five scapular fractures were displaced more than five millimeters. Physical therapy was begun three days to two weeks after the injury. Patients were evaluated with three separate scoring systems: those of Herscovici et al., Rowe, and Constant and Murley. Shoulder abduction and flexion were measured, and abduction strength was evaluated by clinical examination and comparison with the uninjured extremity. The duration of follow-up averaged twenty-eight months (range, nine to seventy-nine months). RESULTS: Nineteen of the twenty pairs of fractures united uneventfully. One clavicular nonunion occurred secondary to segmental bone loss from a gunshot wound. On the basis of the Herscovici rating system, seventeen patients had an excellent result and three had a good result. According to the Rowe system, eighteen patients had an excellent result, one had a good result, and one had a fair result. The average Rowe score was 95. The average Constant score was 96. In all twenty patients, the strength of the injured extremity was equal to that of the uninjured extremity. Eighteen patients had a full, symmetrical range of shoulder motion, one lost 15 degrees of flexion, and one lost 20 degrees of abduction. CONCLUSIONS: Nonoperative treatment of floating shoulder injuries, especially those with less than five millimeters of fracture displacement, can achieve satisfactory results that are probably equal or superior to those reported after operative treatment, without the risk of operative complications.

Adolescent↗
PubMed1999

Infratentorial atrophy on magnetic resonance imaging and disability in multiple sclerosis.

Loss of tissue volume in the central nervous system may provide an index of fixed neurological dysfunction in multiple sclerosis. Recent magnetic resonance studies have shown a modest relationship between clinical disability rating scores and transverse sectional area of the cervical spinal cord. To explore further the relationship between atrophy and disability in multiple sclerosis, we estimated the volumes of infratentorial structures from MRIs in a cross-sectional study of 41 patients, 21 with relapsing-remitting multiple sclerosis and 20 with secondary progressive multiple sclerosis. We used the Cavalieri method of modern design stereology with point counting to estimate the volume of brainstem, cerebellum and upper cervical spinal cord from three-dimensional MRIs acquired with an MPRAGE (Magnetization-prepared Rapid Acquisition Gradient Echo) sequence. The volume of the upper (C1-C3) cervical spinal cord was significantly correlated with a composite spinal cord score derived from the appropriate Functional Scale scores of the Expanded Disability Status Scale (r = -0.50, P < 0.01). The cerebellar (r = 0.49, P < 0.01) and brainstem (r = 0.34, P < 0.05) volumes correlated with the Scripp's Neurological Disability Rating Scale scores. The upper cervical cord volumes (r = -0.39, P < 0.01), but not the brainstem or cerebellar volumes, were significantly associated with disease duration. MRI-estimated structural volumes may provide a simple index of axonal and/or myelin loss, the presumed pathological substrates of irreversible impairment and disability in multiple sclerosis.

Activities of Daily Living↗
PubMed1999

Reading? ... pah! (I got it!). Innovative Reading Technique For Successful Deaf Readers.

A reading program utilizing five components--a shortcut to phonemic awareness, Adapted Dolch words, Bridge lists and the Bridging process, reading comprehension, and American Sign Language development/language experience stories--was administered to 48 elementary school students at a residential school for the deaf. Data analyses reveal dramatic gains in students' reading levels and academic behavior, teachers' growth in reflective sign skills, and students' and teachers' overall growth in ASL skills, resulting in a more organized, consistent approach to linguistic input and usage.

Child↗
PubMed1996

Slow rate of phosphodiester bond formation accounts for the strong bias that Taq DNA polymerase shows against 2',3'-dideoxynucleotide terminators.

Taq and T7 DNA polymerases have become basic molecular biology "tools" for DNA sequence analysis. However, Taq, unlike T7 DNA polymerase, is strongly biased against the incorporation of 2',3'-dideoxynucleotide triphosphates (ddNTPs) indicating very different substrate selectivities. Equilibrium binding and rate constants were measured for 2',3'-ddNTPs as well as for several other 3'-substituted terminators and compared to 2'-deoxynucleotide substrates (dNTPs). In steady-state experiments, Taq Pol I was strongly biased in favor of dATP1 over ddATP incorporation by about 700 to 1, in contrast to T7 DNA polymerase which showed a preference of only about 4 to 1. Manganese reduced but did not eliminate selectivity against 2',3'-ddNTPs. Transient kinetic traces indicated different rate-limiting steps for substrate and terminator incorporation. Further mechanistic studies showed that the binding constants for substrates and terminators were equivalent. However, the rate constants for phosphodiester bond formation for 2',3'-ddNTPs were 200-3000-fold lower than for dNTPs. Alternative terminators showed only slight improvements. The data were consistent with a model in which both substrates and terminators undergo ground-state binding followed by formation of a tight-binding Enz.DNA.Nucleotide complex. Immediately after complex formation, substrates undergo a rapid nucleoside phosphoryl transfer reaction. However, the reaction rates for terminators were slower presumably due to misalignment of reactive groups in the active site. Thus, the strong bias that Taq DNA polymerase shows against terminators is due to a very slow "chemistry" step. Such a strong bias has several kinetic consequences for DNA sequence patterns. These consequences are discussed in the text.

Base Sequence↗
PubMed1991

A defect in insulin release in women at risk of future non-insulin-dependent diabetes.

1. A study on seven Caucasian glucose-tolerant women with previous gestational diabetes and seven matched control subjects is presented. The insulin response to oral glucose, insulin sensitivity and fasting glucose production rates were measured by using a 75 g oral glucose tolerance test, an insulin tolerance test and a non-radioactive tracer, [6,6-2H]glucose, respectively. 2. Fasting plasma glucose levels were similar between the women with previous gestational diabetes and the control subjects (4.8 +/- 0.3 versus 4.7 +/- 0.2 mmol/l), as were fasting plasma insulin levels (median 4 m-units/l, range 1-13 m-units/l versus median 4 m-units/l, range 1-24 m-units/l). After oral glucose the 60 min plasma glucose levels in the women with previous gestational diabetes were significantly higher (8.5 +/- 0.6 versus 6.7 +/- 0.8 mmol/l, P less than 0.05), whereas the plasma insulin level was significantly lower at both 30 min (median 23 m-units/l, range 4-47 m-units/l versus median 55 m-units/l, range 23-100 m-units/l, P less than 0.02) and at 60 min (median 23 m-units/l, range 4-43 m-units/l versus median 60 m-units/l, range 16-126 m-units/l, P less than 0.02). 3. Insulin sensitivity, expressed as the slope of the regression line of plasma glucose level against time after intravenous infusion of insulin (0.05 unit/kg), was similar in the women with previous gestational diabetes and the control subjects (mean slope, -0.17 +/- 0.01 versus -0.17 +/- 0.01). 4. Fasting glucose production rates were similar in the women with previous gestational diabetes and the control subjects (2.2 +/- 0.3 versus 1.9 +/- 0.1 mg min-1 kg-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗