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Biomedical subjects

A Steven

Publications and source records attributed to A Steven.

6 recordsLinked to original sources
PubMed2000

Dis-assembly lines: the proteasome and related ATPase-assisted proteases.

Self-compartmentalizing proteases, such as the proteasome and several prokaryotic energy-dependent proteases, are designed to act in the crowded environment of the cell. Proteins destined for degradation are recognized and unfolded by regulatory subcomplexes that invariably contain ATPase modules, before being translocated into another subcomplex, the proteolytic core, for degradation. The sequential actions effected on substrates are reflected in the linear arrangement of these subcomplexes; thus, the holocomplexes are organized as molecular disassembly and degradation lines.

Adenosine Triphosphatases↗
PubMed2000

Nasogastric feeding in severe acute pancreatitis may be practical and safe.

BACKGROUND: Severe acute pancreatitis may be protracted and some form of nutritional support is frequently required to maintain the patient's nutritional status. Recent work has suggested that enteral feeding via a jejunal route of delivery may reduce the magnitude of the inflammatory response. Insertion of nasojejunal (NJ) tubes in the patient with severe acute pancreatitis involves both delay and inconvenience. We undertook a prospective, feasibility study to assess the safety and practicability of nasogastric (NG) feeding in patients with severe acute pancreatitis. PATIENTS AND METHODS: Twenty-six patients with objective evidence of severe acute pancreatitis received nasogastric feeding within 48 h of admission to our unit. RESULTS: Etiology was identified as cholelithiasis (18 patients), ethanol (5), and miscellaneous (3). The median Glasgow score was 4 (range 2-7), APACHE II score 10 (4-28), and C-reactive protein concentration 286 mg/L (79-469). Fifteen patients had pancreatic and/or peripancreatic necrosis. Eleven patients developed severe organ failure, necessitating ventilatory support. Six developed multiple organ system failure, requiring inotropic support and/or renal dialysis. There were four deaths (15.3%). Nine patients underwent early, and nine late, ERCP, respectively; six necrosectomy (5 proven infected necrosis, 1 continued deterioration despite maximal support) and 4 patients internal drainage of a pseudocyst. The feed was well-tolerated in 22 patients. In 3 patients gastric stasis proved troublesome. There was no evidence of clinical or biochemical deterioration on commencing nasogastric feeding. CONCLUSION: It would appear that early NG feeding is usually possible in severe acute pancreatitis. In most patients it appears safe, well-tolerated, and worthy of further study.

Acute Disease↗
PubMed1999

Editorial

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Journal Article↗
PubMed1999

Named nursing: in whose best interest?

This paper explores certain influences and issues surrounding the implementation and application of the named nurse concept. The author critically examines the proposals that primary nursing increases job satisfaction, cost effectiveness and quality of care, and suggests that as primary nursing appears to be the template for named nursing, these are factors which may have influenced the former British government's decision to implement the concept of named nursing. Owing to problems regarding the reliability and validity of much of the research, the author draws the conclusion that the direct extrapolation from one concept (such as primary nursing) to another (such as named nursing) is perhaps open to question. The author also analyses other issues related to the implementation and use of the named nurse concept including advocacy and accountability, and proposes that the introduction of individualized care, and in particular named nursing, perhaps serves the drive towards the professionalization of nursing first, and the patient second, and if so questions whether there is a need to reconsider the aim of nursing.

Cost-Benefit Analysis↗
PubMed1999

Assembly of the herpes simplex virus procapsid from purified components and identification of small complexes containing the major capsid and scaffolding proteins.

An in vitro system is described for the assembly of herpes simplex virus type 1 (HSV-1) procapsids beginning with three purified components, the major capsid protein (VP5), the triplexes (VP19C plus VP23), and a hybrid scaffolding protein. Each component was purified from insect cells expressing the relevant protein(s) from an appropriate recombinant baculovirus vector. Procapsids formed when the three purified components were mixed and incubated for 1 h at 37 degrees C. Procapsids assembled in this way were found to be similar in morphology and in protein composition to procapsids formed in vitro from cell extracts containing HSV-1 proteins. When scaffolding and triplex proteins were present in excess in the purified system, greater than 80% of the major capsid protein was incorporated into procapsids. Sucrose density gradient ultracentrifugation studies were carried out to examine the oligomeric state of the purified assembly components. These analyses showed that (i) VP5 migrated as a monomer at all of the protein concentrations tested (0.1 to 1 mg/ml), (ii) VP19C and VP23 migrated together as a complex with the same heterotrimeric composition (VP19C1-VP232) as virus triplexes, and (iii) the scaffolding protein migrated as a heterogeneous mixture of oligomers (in the range of monomers to approximately 30-mers) whose composition was strongly influenced by protein concentration. Similar sucrose gradient analyses performed with mixtures of VP5 and the scaffolding protein demonstrated the presence of complexes of the two having molecular weights in the range of 200,000 to 600,000. The complexes were interpreted to contain one or two VP5 molecules and up to six scaffolding protein molecules. The results suggest that procapsid assembly may proceed by addition of the latter complexes to regions of growing procapsid shell. They indicate further that procapsids can be formed in vitro from virus-encoded proteins only without any requirement for cell proteins.

Animals↗