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Biomedical subjects

D G Jones

Publications and source records attributed to D G Jones.

At least 37 records · Page 2Linked to original sources
PubMed2000

Modulation of gammadelta T cells and CD1 in Mycobacterium avium subsp. paratuberculosis infection.

M.a. paratuberculosis is the causal agent of paratuberculosis (Johne's disease). Recent work has suggested that gammadelta T cells may play an important role in the early immunological response to mycobacterial diseases, and that CD1 may act as a non-classical MHC molecule in antigen presentation to these gammadelta T cells. Experimental infection of neonatal lambs with M.a. paratuberculosis was used to investigate the changes in gammadelta T cells and CD1 molecules in the gut associated lymphoid tissue 4 weeks after inoculation. Immunohistochemistry was used to label the gammadelta lymphocytes and CD1 molecules. An increase in the number of gammadelta T cells was noted in both the jejunal and ileal Peyer's patches in the gut of infected lambs, but no statistically significant change was found in the mesenteric lymph nodes. There were no obvious changes in the CD1 molecules in any tissue. This work suggests that gammadelta T cells may play a role in the initial immunological events of paratuberculosis infection.

Animals↗
PubMed2000

What is anatomy? Implications for anatomy as a discipline and for Clinical Anatomy as a journal.

Anatomy as a discipline is explored against a background of the growth of scientific knowledge and developments within modern universities. The structural overtones of anatomic approaches provide intellectual cohesion for the approaches of complementary disciplines. When anatomy departments function in a transdisciplinary manner, they encompass a range of areas from molecular biology to functional anatomy and biological anthropology. Suggestions are made for a journal, such as Clinical Anatomy, to provide stimulus for the further development of anatomy as a coherent discipline.

Anatomy↗
PubMed2000

The fine connective tissue architecture of the human ligamentum nuchae.

STUDY DESIGN: An anatomic study of the posterior midline structures of the cervical spine was performed using a new sheet-plastination (E12) technique in conjunction with gross anatomic dissection. OBJECTIVES: To clarify the structural status of the human ligamentum nuchae. SUMMARY OF BACKGROUND DATA: Little is known about the arrangement of connective tissue attachments of the neighboring neck muscles to the ligamentum nuchae. In addition, it is not clear whether the cervical supraspinous ligaments form part of the ligamentum nuchae. METHODS: This study used a combined approach of a detailed gross anatomic study on eight cadavers and a macroscopic and microscopic study of the connective tissue organization of the posterior midline structures on serial horizontal thin (2.5 mm) plastinated slices of the cervical spine (occiput-T1) from an adult female cadaver. RESULTS: The dorsal and ventral portions of the ligamentum nuchae are a single entity formed by the aponeurotic fibers of the trapezius, splenius capitis, rhomboideus minor, and serratus posterior superior muscles. CONCLUSIONS: The regional differences in the connective tissue organization of the ligamentum nuchae and its well-defined attachments to the C6 and C7 vertebrae suggest that it is designed to function in the lower cervical spine.

Aged↗
PubMed2000

Overcoming representational errors in complex environments.

Errors in situation awareness (SA) can degrade the decision process. One particularly troublesome SA error is the representational error, which reflects problems with the misinterpretation of information based on a person's current mental model of a situation. This study investigates whether the schema-relatedness of information affects the likelihood that a person will fall prey to a representational error. Using a high-fidelity simulation of an air traffic control task, two hypotheses were examined: (a) Schema-bizarre information will affect SA more than schema-irrelevant information, and (b) schema-unexpected information will impact SA more than the absence of schema-expected information. The results supported the first hypothesis but not the second. These results provide an indication of the types of information that affect SA. Enhancing SA by emphasizing the type of information to which an operator is naturally less inclined to respond is one approach to improving system design and thereby performance.

Aircraft↗
PubMed1999

Homologous plasminogen N-terminal and plasminogen-related gene A and B peptides. Characterization of cDNAs and recombinant fusion proteins.

The cDNA corresponding to exons 2-4 of the processed human plasminogen (Pgn) gene, encoding the N-terminal peptide domain (NTP), has been cloned, expressed in Escherichia coli as a recombinant protein (r-NTP) containing a hexahistidine tag, and refolded to the native structure that contains two internal cystine bridges. RNA expression of the two Pgn-related genes, PRG A and PRG B, that potentially encode 9-kDa polypeptides having extensive similarity to the NTP has been investigated. Using RNA-based PCR with liver RNA as template, we demonstrate that PRG A encodes a detectable mRNA species. PRG A and PRG B have been found to be transcribed in the liver and yield virtually identical mRNAs. Neither of the PRGs are expressed in a variety of other normal tissues, as determined by Northern blot analysis. Factor-Xa digestion of the tagged r-NTP yields cleavage products which indicates that the expressed r-NTP domain of Pgn is endowed with a flexible conformation. Recombinant PRG B protein (r-PRG B) fused to a hexahistidine tag was purified and analyzed for structural integrity. Preliminary 1H-NMR spectroscopic data for r-NTP and r-PRG B indicate relatively fast amide 1H-2H exchange in 2H2O and close conformational characteristics for the two homologous polypeptides. Far ultraviolet-CD spectra for r-NTP and r-PRG B at pH 7.0 indicate similar defined secondary structure content for both domains, with 13-17% alpha-helix and 24-27% antiparallel beta-sheet. The fact that two transcriptionally active genes encode almost identical polypeptides supports the hypothesis that the Pgn NTP, together with the putative polypeptides encoded by the PRGs, may serve an important function, such as controlling the conformation of Pgn and thus its susceptibility to tissue activators.

Amino Acid Sequence↗
PubMed1999

Posterior peripheral sutures in meniscal allograft replacement.

In our experience, meniscal allograft transplantation does have a role after a total or a significant partial meniscectomy in young to middle-aged symptomatic patients. While the quality of the meniscal tissue is crucial to the success of the operation, it is equally important to duplicate the mechanical function of the original semilunar cartilage and assure a secure peripheral attachment of the meniscal implant. The technique for peripheral meniscal suture placement described in this article permits an easier and more secure attachment of the posterior third of the implant to the joint capsule.

Adult↗
PubMed1999

Posterior cruciate ligament injuries of the knee joint.

Posterior cruciate ligament (PCL) injuries have a reported incidence of between 3 and 37%, depending on the clinical setting. The most common mechanism of injury in motor vehicle accidents is a dashboard injury or direct force to the proximal anterior tibia. Sports related injuries result from hyperflexion of the knee with the foot typically plantarflexed. The latter mechanism is the most common cause of isolated PCL injuries, while in the trauma population as many as 95% of patients with knee injuries have combined ligamentous damage. Improved knowledge at an anatomical, biomechanical and clinical level has provided the orthopaedist with a more defined treatment algorithm. Isolated, partial PCL injuries (grades I and II) can best be treated nonoperatively while complete injuries (grade III) may require operative treatment based on clinical symptoms. All combined ligamentous injuries usually respond best with surgical management.

Athletic Injuries↗