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Biomedical subjects

B Barker

Publications and source records attributed to B Barker.

35 records · Page 2Linked to original sources
PubMed1986

Multiple trauma associated with vertebral injury.

Three hundred twenty-two vertebral fractures in multiply injured patients are reviewed. Associated general trauma was usually found to be regionalized to the same area of the body as the spinal injury. The exceptions were pelvic and sacral fractures, which were associated with more diffuse organ injury and multiple vertebral fractures.

Adolescent↗
PubMed1985

MR imaging using specialized coils.

The purpose of this study was to evaluate the clinical utility of specialized coils with magnetic resonance (MR) imaging and to determine the potential improvement in the signal-to-noise ratio (SNR) provided by the various coils. A total of 48 patients were studied-33 with surface coils and 15 with limb coils. MR imaging was performed with a superconducting magnet operating at 0.35 T. Two applications of surface coils were evaluated; one used for both transmitting and receiving and the other used only for receiving. Structures studied with the surface coils included the orbit, carotid artery, cervical and lumbar spine, parotid and thyroid glands, other neck structures, femoral artery, kidney, prostate, hip, and heart. The regions studied with the limb coil were the ankle, knee, wrist, elbow and popliteal artery. We calculated the SNR, and the results demonstrated a marked improvement with the specialized coils: a twofold increase for the 10-cm surface coil versus the head coil and a 4.6-fold increase compared with the body coil, a 2.3-fold increase for the 20-cm surface coil compared with the body coil, and 2.8- and 6.4-fold increases for the limb coil versus the head coil and the body coil, respectively. The use of specialized coils was feasible in the clinical setting and they provided a marked improvement in the image SNR, which facilitated the imaging of small and superficial structures.

Adolescent↗
PubMed1984

An investigation of S-100 protein in embryonic dental papillae of rats.

We attempted to identify S-100 protein, a marker of neural crest tissue, within cells of the developing dental papillae of 18-day rat fetuses by means of the immunoperoxidase technique. Although there is experimental evidence that dental papillae are derived from neural crest, no marker protein was identified in this study.

Animals↗
PubMed1984

Magnetic resonance imaging strategies for heart studies.

Given a suitable trigger signal, cardiac synchronized magnetic resonance (MR) imaging is simple to implement; however, single section techniques are not efficacious, especially when the heart rate sets the repetition interval. We demonstrate multi-section, double, and single-echo imaging, any of which rapidly covers the cardiac volume; 3-D modes capable of achieving very thin sections; and cycled multi-section imaging capable of efficaciously providing dynamic data on heart motion. These modes form a complementary, powerful set of options for clinical work.

Heart↗
PubMed1980

Infarct distribution in subhuman primates after acute coronary occlusion.

The extent of epicardial, endocardial and septal infarct was determined in 24 monkeys and five baboons 1 week after acute left anterior descending or diagonal branch coronary artery ligation. All 24 Macaca cynmologous monkeys had non-dominant left anterior descending coronary arteries. A snare ligature was placed just distal to the first diagonal branch for varying time periods (1, 2, 4, and 6 h followed by reperfusion or left in place permanently). In five baboons a chronic ligature was placed around a diagonal branch. All animals lived and were killed a week later. Histological mapping and planimetry of serial cross-sections were employed to quantify the extent and distribution of the infarct. All infarcts were transmural. The extent of epicardial infarct was significantly greater than the extent of endocardial infarct for 2 h ligations (3.5 +/- 0.87% of the left ventricle versus 2.4 +/- 0.58% of the left ventricle, P less than 0.05), the chronic left anterior descending coronary artery ligations (5.4 +/- 1.06% of the left ventricle versus 4.5 +/- 0.92% of the left ventricle, P less than 0.05 and for the chronic diagonal branch ligations (4.06 +/- 0.66% of the right ventricle + left ventricle versus 2.64 +/- 0.51+ of the right ventricle + left ventricle, P less than 0.02). It is evident, however, that the magnitude of this epicardial preponderance was not great and that, in general, the infarcts were transmural and rectangular in configuration.

Animals↗
PubMed1971

Properties of bacteriophage T4 mutants defective in gene 30 (deoxyribonucleic acid ligase) and the rII gene.

In Escherichia coli K-12 strains infected with phage T4 which is defective in gene 30 [deoxyribonucleic acid (DNA) ligase] and in the rII gene (product unknown), near normal levels of DNA and viable phage were produced. Growth of such T4 ligase-rII double mutants was less efficient in E. coli B strains which show the "rapidlysis" phenotype of rII mutations. In pulse-chase experiments coupled with temperature shifts and with inhibition of DNA synthesis, it was observed that DNA synthesized by gene 30-defective phage is more susceptible to breakdown in vivo when the phage is carrying a wild-type rII gene. Breakdown was delayed or inhibited by continued DNA synthesis. Mutations of the rII gene decreased but did not completely abolish the breakdown. T4 ligase-rII double mutants had normal sensitivity to ultraviolet irradiation.

Coliphages↗
PubMed1967

A suggested approach to a library building program.

The preliminary building program suggested in this paper makes use of outlines, graphs, charts, and lists, rather than long-winded paragraphs, to describe the needs, objectives, and philosophy of the library. It is hoped that a short, concise, but detailed, report using these methods will save time and make the report more attractive to read, thereby encouraging the many people who will need to assist in the building planning to use the report.

Architecture↗
PubMedDate not supplied

Effect of perfusion on exercised muscle: MR imaging evaluation.

An ischemic clamp model of exercise was used to evaluate the potential role of blood flow in mediating changes in the magnetic resonance imaging appearance of skeletal muscle. Proton relaxation times of muscle were serially estimated in 10 healthy subjects (a) before exercise, (b) after exercise in the presence of vascular occlusion (VO1), (c) during vascular reocclusion after 1 minute of reperfusion (VO2), and (d) after reinstitution of continuous flow. T1 and T2 of active muscles were increased during VO1. During VO2, there were additional increases in relaxation times of active muscles. Reinstitution of continuous flow was associated with a continuous decrease in the T2 of exercised muscle. Hence, blood flow was not required for increases in T1 and T2 with exercise. Additional relaxation time increases occurred after a brief period of reperfusion; however, continuous flow was associated with a decrease in T2.

Adult↗
PubMedDate not supplied

The Filshie clip for laparoscopic adnexal surgery.

BACKGROUND: Gynecologic endoscopic procedures are increasingly common and require the ability to control large vascular structures. METHOD: The Filshie clip is a silicone-lined, titanium occlusive device, originally designed and Food and Drug Administration (FDA) approved for surgical contraception. This device also has the potential for occluding vascular structures during laparoscopic surgery. EXPERIENCE AND RESULTS: We describe a salpingectomy, an excision of bilateral hydrosalpinges, and a salpingo-oopherectomy. We performed all procedures laparoscopically using this device as the primary modality for assuring hemostasis. CONCLUSION: The Filshie clip is a useful and economical device for assuring hemostasis during gynecologic endoscopic surgery.

Adnexa Uteri↗