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Biomedical subjects

T Briggs

Publications and source records attributed to T Briggs.

At least 19 recordsLinked to original sources

Retraining: can do, will do? A practical guide to process and pitfalls.

This article reports the lessons learnt from a period of retraining and from discussion with others who have been involved in a similar process. The conclusions are that retraining should only be undertaken once there is full agreement between all parties involved that it is necessary and feasible. There must also be agreement in advance of the criteria which will constitute successful retraining, and the actions which will be taken to ensure the rapid return of the retrainee to the type of practice which is being offered and has been accepted. The process of retraining requires especially close supervision and is very stressful for the retrainee. It is likely that this should only be undertaken in units specially staffed and funded to accommodate this type of work.

Clinical Competence↗

A histomorphological study of tendon reconstruction to a hydroxyapatite-coated implant: regeneration of a neo-enthesis in vivo.

The attachment of tendons and ligaments to massive endoprostheses remains a clinical challenge due to the difficulty in achieving a soft tissue implant interface with a mechanical strength sufficient to transmit the forces necessary for locomotion. We have used an in vivo animal model to study patellar tendon attachment to an implant surface. The interface generated when the patellar tendon was attached to a hydroxyapatite (HA) coated implant was examined using light microscopy and a quantitative histomorphological analysis was performed. In the Autograft Group, the interface was augmented with autogenous cancellous bone and marrow graft, and at six weeks an indirect-like insertion was observed. At twelve weeks, the interface was observed to be a layered neo-enthesis, whose morphology was similar to a normal direct tendon insertion. In the HA Group, the tendon-implant interface was not augmented, and the implant was enveloped by a dense collagenous fibrous tissue. This study shows that a tendon-implant neo-enthesis can develop in situ by employing a suitable implant surface in association with biological augmentation.

Animals↗

Single center experience of a new intensive induction therapy for ewing's family of tumors: feasibility, toxicity, and stem cell mobilization properties.

PURPOSE: To examine the feasibility, tolerability, and toxicity of an intensified induction regimen (vincristine, ifosfamide, doxorubicin, and etoposide [VIDE]) in patients with newly diagnosed Ewing's family of tumors (EFT); to assess ability to maintain dose-intensity, and predictability of peripheral-blood stem cell mobilization. PATIENTS AND METHODS: Thirty patients were treated with vincristine 1.4 mg/m2 (maximum 2 mg) on day 1, doxorubicin 20 mg/m2, ifosfamide 3 g/m2 plus mesna and etoposide 150 mg/m2 on days 1 to 3. Cycles were given every 21 days for up to six cycles. RESULTS: One-hundred and seventy cycles of VIDE were given. The median treatment interval was 21 days (21 to 42) and nadir count: hemoglobin 8.3 (6.3 to 11.9), neutrophils 0.045 (0.0 to 2.1), and platelets 45 (3 to 343). There were 96 episodes of infection requiring hospitalization (56%). Growth factor support reduced infectious complications by 34%. Etoposide dose was reduced, or omitted, in 24% of cycles. Four patients did not complete six cycles due to unacceptable toxicity and one patient progressed on treatment. Twenty patients underwent peripheral-blood stem cell harvesting, 15 after cycle 3, and five after cycle 4. Median CD34+ yield was 4.6 x 106/kg per patient (1.8 to 14.5). Overall response to treatment, measured in 24 patients, was 88%. Seven of 11 patients undergoing surgery achieved greater than 90% necrosis of tumor (64%). CONCLUSION: VIDE is an effective induction regimen with substantial but acceptable toxicity that allows predictable mobilization of stem cells. Maintenance of dose-intensity is feasible in the majority of patients. Growth factors play a role in maintaining dose-intensity and reduce infectious complications.

Adolescent↗

Transcriptional repression by neuron-restrictive silencer factor is mediated via the Sin3-histone deacetylase complex.

A large number of neuron-specific genes characterized to date are under the control of negative transcriptional regulation. Many promoter regions of neuron-specific genes possess the repressor element repressor element 1/neuron-restrictive silencing element (RE1/NRSE). Its cognate binding protein, REST/NRSF, is an essential transcription factor; its null mutations result in embryonic lethality, and its dominant negative mutants produce aberrant expression of neuron-specific genes. REST/NRSF acts as a regulator of neuron-specific gene expression in both nonneuronal tissue and developing neurons. Here, we shown that heterologous expression of REST/NRSF in Saccharomyces cerevisiae is able to repress transcription from yeast promoters engineered to contain RE1/NRSEs. Moreover, we have taken advantage of this observation to show that this repression requires both yeast Sin3p and Rpd3p and that REST/NRSF physically interacts with the product of the yeast SIN3 gene in vivo. Furthermore, we show that REST/NRSF binds mammalian SIN3A and HDAC-2 and requires histone deacetylase activity to repress neuronal gene transcription in both nonneuronal and neuronal cell lines. We show that REST/NRSF binding to RE1/NRSE is accompanied by a decrease in the acetylation of histones around RE1/NRSE and that this decrease requires the N-terminal Sin3p binding domain of REST/NRSF. Taken together, these data suggest that REST/NRSF represses neuronal gene transcription by recruiting the SIN3/HDAC complex.

Cell Line↗

Attitudes of carers and the elderly occupants of residential homes to antimicrobial chewing gum as an aid to oral health.

OBJECTIVE: The aim of this study was to investigate the attitudes of elderly residents to using an antimicrobial chewing gum as an aid to oral health, and the opinion of their carers on such a procedure. DESIGN: A cross-sectional, multi-centre survey using a structured interview/questionnaire conducted with elderly residents and their carers. SETTING: In January 1998, 9 residential/nursing homes were chosen at random from all the homes in West Hertfordshire, 207 residents were asked to chew two pieces of gum twice daily for 7 days. SUBJECTS: The participants, 148 women and 59 men, were aged between 53-100 years (mean age 82.23 +/- 9.62 years). 47 carers, all female, were involved in distributing and collecting the gum. RESULTS: 122 residents (58.9%) were edentulous and 85 (41%) of the participants were partially dentate. Of those with teeth 23 (27%) had 21 teeth or more. 73 (35.2%) residents found that chewing the gum was difficult with 37 (17.9%) of this group being unable to chew (P < 0.0001 for those residents with no teeth/dentures or dentures unopposed by teeth or other dentures). 32 (18.6%) subjects disliked the flavour of the gum. Of the 170 residents who chewed the gum 99 (57.2%) found it reduced oral dryness and 78 (45.1%) reported it made their mouth feel healthy. 34 (53.6%) of the dentate and 47 (40.9%) of the edentate residents wished to keep using the gum (P < 0.05). 35 (74.5%) of the carers found it easy to distribute the gum and 29 (61.7%) thought that chewing gum was an acceptable method of maintaining oral health for residents. CONCLUSION: The antimicrobial gum investigated in this study was acceptable to many elderly occupants and their carers, significantly improving perceived oral health and oral dryness of residents.

Aged↗

A computer generated interactive transurethral prostatic resection simulator.

PURPOSE: We developed a computer generated model of the prostate gland and an interactive simulator for use in training urologists in transurethral resection of the prostate. MATERIALS AND METHODS: Software was developed on a standard personal computer which allowed images of the lumen of the prostatic urethra and resectoscope loop to be generated and interacted with using a magnetic position sensor input device attached to a dummy resectoscope. RESULTS: An anatomically accurate computer model of the prostate was generated at low cost which permitted user interaction and which simulated key elements of transurethral prostatic resection. CONCLUSIONS: Although not a substitute for learning transurethral prostatic resection on patients, the simulator enabled the user to become familiar with the technique of transurethral prostatic resection in the absence of time constraints and without risk to patients. The simulator may become an important tool in training and assessing surgeon competency, and may reduce the costs of training. Further development is needed to refine the transurethral prostatic resection simulator and expand its surgical range.

Computer Simulation↗

Hazard of ionizing radiation to trauma surgeons: reducing the risk.

A study aimed to establish the level of radiation exposure to orthopaedic surgeons involved in the care of injured patients; parts of the body most at risk, and to establishing whether surgeon control of X-ray image intensification reduced the risk. This was conducted on five orthopaedic surgeons regularly involved in musculoskeletal care. Radiation dosage (in millisieverts (mSv) to the body, neck, eyes and hands, was measured by means of dosimeters applied to these areas, before and after surgeon-controlled use of X-ray image intensification. Although all doses measured were within current safety guidelines (1.25 mSv total body dose/month, 3.75 mSv eye dose/month and 12.5 mSv extremity dose/month), the hands were most at risk (maximum recorded dosage 3.95 mSv/month). Control by the surgeons of X-ray image intensification significantly reduced exposure of the hands (P < 0.05).

Eye↗

Notes: a suitable case for audit.

The increasing emphasis on management responsibilities and audit led us to investigate the state of surgical notes in our hospital. Twelve criteria were evaluated regarding information that should be contained in the notes and the absence of this important information was documented. Deficiencies were revealed in all criteria selected. Until hospital patients files are well kept and maintained, retrospective audit whether financial or medical will not be valid. A significant injection of resources is required to redress the situation. Hospitals which have not carried out detailed studies into the contents of their notes need to do so as a matter of urgency.

Humans↗

Lipolysis of serum-activated triacylglycerol at the surface of J774.1 macrophages. A biochemical--electron-microscopic study.

Cultured mouse (J774.1) macrophages accumulated triacylglycerol, but no cholesteryl ester or cholesterol, when incubated in albumin-poor medium with serum-activated lipid particles containing 84 mol% trioleoylglycerol and 9 mol% cholesteryl oleate. Accumulation of triacylglycerol by cells was associated with hydrolysis of particulate triacylglycerol to fatty acid and glycerol. Both acyl and glyceryl moieties of particulate triacylglycerol were recovered in cellular triacylglycerol with a molar ratio of 3.6. The cells also accumulated fatty acid and monoacylglycerol. Whether acylglycerol was taken up as a single molecular species, such as monoacylglycerol, or as several species can not be determined by the present findings. Macrophages incubated with lipid particles for 24 h had many lipid particles attached to cell surfaces and numerous intracellular lipid droplets. The surface film of attached particles was continuous with the outer leaflet of plasma membrane of the cells. Particles partially depleted of core triacylglycerol and collapsed surface films were found attached to surfaces of macrophages. There was no morphological evidence that lipid particles were taken up intact by cells, through endocytosis or phagocytosis. Macrophages incubated with lipid particles also contained intracellular lamellar structures. They varied in size and shape, and were located in the periphery of cells, sometimes near lipid droplets and endoplasmic reticulum. Only 3% of the lamellar structures were associated with lysosomes, indicating they probably were not of lysosomal origin. Lipid particles attached to cells decreased in size and number, and lamellar structures developed at the surface of particles, or replaced the particles, when glutaraldehyde-fixed specimens were incubated at 25 degrees C, demonstrating lipolytic activity at the surface of macrophages. Our findings suggest that particulate triacylglycerol was hydrolyzed by lipoprotein lipase at the surface of macrophages, and that fatty acid and monoacylglycerol formed by lipolysis were transported directly into the cells to be reesterified. When lipolytic products were taken up faster than they could be utilized, they accumulated as lamellar structures in the cells.

Animals↗

Comparison of the bile salts of frogs with those of their tadpoles. Bile-salt changes during the metamorphosis of Rana Catesbeiana Shaw.

1. The bile salts of three frog species of the genus Ptychadena and of Rana catesbeiana have been compared with those of their tadpoles. For R. catesbeiana comparison was made of the bile salts in at least ten of the recognized stages of tadpole metamorphosis. 2. In all cases, adult bile salts were more complex than those of the tadpoles. 3. In R. catesbeiana after stage 18, 26-deoxy-5 alpha-ranol was hydroxylated to form 5 alpha-ranol (27-nor-5 alpha-cholestane-3 alpha, 7 alpha, 12 alpha, 24 xi, 26-pentol) and at least two other bile alcohols appeared in solvolysed bile salts. 4. Tadpole bile salts were not found to be biochemically more primitive than those of fully metamorphosed frogs; in some, but not all, cases tadpole bile alcohols could be regarded as biochemical precursors of those in the adult frogs. 5. Detailed evidence for the structure of the bile salts from mass-spectral fragmentation patterns has been deposited as Supplementary Publication SUP 50097 (2 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

Animals↗