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Biomedical subjects

D Jones

Publications and source records attributed to D Jones.

At least 469 records · Page 26Linked to original sources
PubMed1993

A frameless method for stereotactic radiotherapy.

A frameless method for stereotactic multiple arc radiotherapy (SMART) is described. Three short gold wires are implanted in the scalp approximately 100 mm apart. These are localized in a computed tomographic or angiographic study along with the target. Subsequently the gold markers are localized on beam films and the target position calculated using a computer program ISOLOC. This program provides the couch movements required to move the target to the isocentre and a micropositioner attached to the couch is used to make the adjustment. Beam films are repeated until the movements required are less than 1 mm in any direction. It is shown that the simple procedures of implanting the markers subcutaneously do not provide a stable reference system in about 25% of patients and the markers are now screwed into the cranium. The precision of the method is evaluated by phantom studies and measurements taken during several hundred treatments.

Brain Diseases↗
PubMed1993

Pre-billing DRG reviews set new standard.

When and how you do DRG review is critical. This piece offers tips on hiring consultants who can help you provide this financially important service.

Abstracting and Indexing↗
PubMed1993

Early experience with homograft aortic root replacement for complex aortic pathology.

BACKGROUND: Complex aortic valve and root pathology presents a serious operative challenge. METHODS: During the last 45 months 21 cryopreserved homograft root replacements have been performed in 19 patients. The ages of the patients ranged from 28 to 77 years; there were 15 men and four women. Six patients had endocarditis, four prosthetic and two native valve endocarditis. One patient underwent homograft aortic root replacement twice; one underwent concomitant homograft right ventricular outflow tract reconstruction for pulmonic endocarditis. Causes of aortic pathology in the other 13 patients included ascending aortic aneurysm with valvular regurgitation in seven, Marfan syndrome in two, and four aortic dissections with aortic regurgitation. Ten of the nineteen patients were undergoing reoperative procedures. RESULTS: There were three hospital deaths and one death at home of unknown cause. Two of the three patients who died in hospital had undergone redo cardiac procedures. Dramatic functional class improvement was seen in all survivors. CONCLUSIONS: Follow-up from 2 to 45 months in the fifteen survivors revealed no clinical or significant echocardiographic evidence of valvular regurgitation or recurrent infection. We believe homograft root replacement provides an excellent method of reconstruction with several advantages unique to human valved conduits, including ease of handling, lack of synthetic nidus for recurrent infection, and absence of thrombogenic materials. Homografts should be considered the approach of choice in complex valvular and root infectious processes.

Adult↗
PubMed1993

Comparative vascular audit using the POSSUM scoring system.

Comparative audit using overall mortality and morbidity figures can be misleading as they do not take into account variations in surgical procedure and patient fitness. To examine these effects we have compared vascular surgery in two differing hospitals, during a similar 9-month period, using the POSSUM scoring system. In one unit, 255 patients underwent vascular surgery with an operative mortality of 9.4%, and morbidity of 37.3%. In the other unit, 89 patients underwent vascular procedures with an operative mortality of 20.2% and morbidity of 47.2%. At first sight there appear to be significant differences in operative outcome between the two units. However, analysis using the POSSUM system predicts a mortality rate of 10.2% for unit A and 20.2% for unit B (morbidity rates of 38.4% for unit A and 50.6% for unit B). Receiver operating curve (ROC) analysis demonstrated no significant difference between the two units (see Table III). POSSUM analysis may be of use in comparative audit.

England↗
PubMed1993

Phenotypic and phylogenetic evidence for a close relationship between Lactococcus garvieae and Enterococcus seriolicida.

Cultural, biochemical and protein profiling studies were performed on L. garvieae strains isolated from diseased rainbow trout and on the fish pathogen Enterococcus seriolicida ATCC 49156. The results, confirmed by 16 rRNA sequence analyses, indicate that E. seriolicida ATCC 49156 should be reclassified in the genus Lactococcus. Contrary to previous reports, both L. garvieae and E. seriolicida were found to be beta-haemolytic.

Animals↗
PubMed1993

Multidisciplinary treatment results for patients with isolated cleft palate.

Fifty-eight patients with cleft palate only who had received treatment in the Department of Otolaryngology-Head and Neck Surgery at the University of Iowa were examined for treatment results. Forty-one (70.7 percent) of the 58 patients showed a syndrome or suggestive factors. An unusually high percentage (36 percent) of the 58 patients required secondary surgery for velopharyngeal dysfunction or showed indications for surgery at examination. Some but not all of the relatively low success rate appears related to surgical experience. Speech proficiency, hearing acuity, and dental status were within normal limits or nearly so. The 20 patients with pharyngeal flap surgery were doing well, with minimal indications of functional obstruction.

Adolescent↗
PubMed1993

The TAPS Project. 11: The selection of patients for reprovision.

The selection of patients for community reprovision during the first three years of an active closure programme at two large mental hospitals in the North East Thames Regional Health Authority was studied. It was found that a strong selection bias was operating: the patients selected were significantly younger, had spent less time in full-time psychiatric care, were less likely to have a diagnosis of schizophrenia, had larger social networks, and were more likely to want to leave hospital.

Activities of Daily Living↗
PubMed1992

Thymic selection of the human T cell receptor V beta repertoire in SCID-hu mice.

Implantation of pieces of human fetal liver and thymus into SCID mice results in the development of a human thymus-like organ, in which sustained lymphopoiesis is reproducibly observed. In this model, T cell development can be experimentally manipulated. To study the influence of thymic selection on the development of the human T cell repertoire, the T cell receptor (TCR) V beta gene repertoire of double-positive (CD4+CD8+) and single-positive (CD4+CD8- and CD4-CD8+) T cells was analyzed in the SCID-hu thymus using a multiprobe ribonuclease protection assay. TCR diversity in double-positive SCID-hu thymocytes was found to be comparable with that present in the thymus of the fetal liver donor, did not change with time, and was independent of the origin of the thymus donor. Thymic selection in SCID-hu thymus induces changes in V beta usage by the single-positive CD4+ or CD8+ T cells comparable with those previously reported for single-positive cells present in a normal human thymus. Finally, significant differences were observed in the V beta usage by CD4 or CD8 single-positive T cells that matured from genetically identical stem cells in different thymic environments. Collectively, these data suggest: first, that the generation of TCR diversity at the double-positive stage is determined by the genotype of the stem cells; and second, that polymorphic determinants expressed by thymic epithelium measurably influence the V beta repertoire of mature single-positive T cells.

Alleles↗
PubMed1992

Quality of life measures in health care. I: Applications and issues in assessment.

Many clinicians remain unsure of the relevance of measuring quality of life to their clinical practice. In health economics quality of life measures have become the standard means of assessing the results of health care interventions and, more controversially, the means of prioritising funding; but they have many other applications. This article--the first of three on measuring quality of life--reviews the instruments available and their application in screening programmes, audit, health care research, and clinical trials. Using the appropriate instrument is essential if outcome measures are to be valid and clinically meaningful.

Clinical Protocols↗
PubMed1992

Sequence, structure, and expression of a wasp venom protein with a negatively charged signal peptide and a novel repeating internal structure.

An expression cDNA library prepared from mRNA from the venom gland of a parasitic wasp, Chelonus sp. near curvimaculatus, was screened with polyclonal antibodies against a 33-kDa venom protein from this wasp. Immunoreactive clones were sequenced, yielding a complete inferred sequence for a protein with an NH2 terminus identical with that of the 33-kDa protein. The structure of the cDNA showed an apparent encoded signal peptide, which was unusual in possessing 2 glutamic acid residues juxtapositioned next to, or replacing, the conventional basic residues. The bulk of the mature protein sequence which follows the NH2-terminal, 5000-kDa hydrophobic domain is composed of a dozen tandem repeats of a highly charged, approximately 14-residue sequence, except for the truncated eighth repeat which terminates in the only proline in this large domain. The primary structure is not closely related to any sequence in the GenBank data bank. Secondary structure analysis identified a turn occurring at or near each of 12 invariantly conserved serine residues. Further, the codon used for this serine was invariant, whereas other serines in the protein (including a nearly invariant serine 2 residues away) used various codons. Results of epitope mapping experiments supported a proposed tertiary structure in which the NH2-terminal 5-kDa forms a hydrophobic core, overlain with the charged repeats. Northern analysis of poly(A) RNA from the venom gland of young adult female wasps showed expression of a single 1-kilobase transcript, for which there is no corresponding message in normal or parasitized host larvae. The remarkable structure of this protein and structural data on other wasp venom proteins suggest an evolutionary pattern in which some proteins critical for venom function evolve by internal tandem duplication, and which are secreted after biosynthesis by a different mechanism from that used for proteins with classical signal peptides containing basic residues.

Amino Acid Sequence↗
PubMed1992

Marek disease virus encodes a basic-leucine zipper gene resembling the fos/jun oncogenes that is highly expressed in lymphoblastoid tumors.

Marek disease virus (MDV) is a herpesvirus of chickens that induces T lymphomas within 3 weeks of infection. The short latency and polyclonal nature of MDV-induced tumors have suggested that the virus may encode one or more direct-acting oncogenes. To date, however, no MDV-specific tumor antigens or candidate transforming genes have been demonstrated. In this paper, we report the identification of a MDV gene encoding a protein with homology to the leucine-zipper class of nuclear oncogenes. It also contains a proline-rich domain characteristic of another class of transcription factors. This gene, designated meq, maps to the long repeat of MDV and is one of the few genes that are highly expressed in MDV-induced T-cell tumors. To our knowledge, a herpesvirus gene closely related to the fos/jun family of oncogenes has not been reported previously.

Amino Acid Sequence↗
PubMed1992

Expression of the polyubiquitin-encoding gene (ubq-1) in transgenic Caenorhabditis elegans.

The expression of the polyubiquitin-encoding gene (ubq-1) of Caenorhabditis elegans was analysed using transgenic nematode lines carrying translational ubq-1::lacZ fusions. Animals carrying a construct consisting of 938 bp of ubq-1 upstream sequences fused to lacZ (ubq938::lacZ) expressed beta Gal in embryos and in a tissue-general manner in 20% of L1 larvae. Somatic expression in later stages was usually confined to body muscle. Progressively larger deletions extending from the 5' end of ubq938::lacZ did not significantly alter the pattern of expression until 827 bp of sequence had been removed. Thus, sequences upstream from the transcription start point, including a G+C-rich block and a sequence resembling a TATA box (GAATAA), are not required to generate the expression pattern seen with ubq938::lacZ. Moreover, a basal level of expression was maintained in embryos when 903 bp were deleted. These results suggest that the promoter elements required for efficient expression of ubq-1 may reside within the transcribed region of the gene; alternatively, they must lie more than 1.7 kb upstream or 0.8 kb downstream from this region. Polymerase chain reaction analysis indicates that RNA molecules transcribed from the ubq938::lacZ and ubq delta 827::lacZ transgenes are trans-spliced to SL1, as is ubq-1 RNA.

Animals↗