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Biomedical subjects

A Scott

Publications and source records attributed to A Scott.

At least 19 recordsLinked to original sources

A case of haemangiopericytoma-associated hypoglycaemia: Beneficial effect of treatment with radiotherapy.

A 72-year-old lady presented with recurrent hypoglycaemia and a large pelvic mass. Hypoglycaemia was accompanied by undetectable serum insulin and c-peptide and high insulin-like growth factor II (IGFII) to IGFI ratio. She had undergone successful resection of a large bladder haemangiopericytoma 7 years earlier. A core biopsy was performed, and histology confirmed the recurrence of the haemangiopericytoma. Local palliative radiotherapy resulted in the reduction of IGFII level and IGFII to IGFI ratio and increased insulin, c-peptide and growth hormone (GH) level with long-term amelioration of hypoglycaemic episodes. Clinically and biochemically, radiotherapy was more effective than GH therapy.

Aged↗

Increased injury and intramuscular collagen of the diaphragm in COPD: autopsy observations.

Evidence for diaphragm injury in people with chronic obstructive pulmonary disease (COPD) has been reported, although the extent of injury and collagen accumulation post mortem have not previously been examined. In addition, it is not known whether the amount of injury and collagen are different in key regions of the diaphragm. The cross-sectional area of collagen and the percentage of abnormal myofibres in the post mortem diaphragm and psoas major were determined by computer-assisted image analysis of stained cross-sections of the diaphragm for collagen with picrosirius red and with haematoxylin and eosin for morphology. In the midcostal diaphragm of six subjects with COPD and six subjects with no significant respiratory disease, the COPD diaphragm displayed a greater cross-sectional area of collagen and percentage of abnormal myofibres (collagen: 24.2+/-1.0 versus 18.6+/-1.1%; injury: 28.4+/-7.2 versus 12.0+/-1.3%). In 18 patients with various respiratory conditions, the midcostal diaphragm displayed more collagen and abnormal myofibres than the crural diaphragm, while both costal and crural diaphragms displaying more collagen and abnormal myofibres than psoas major. This study reveals extensive injury and collagen accumulation in the chronic obstructive pulmonary diseased diaphragm, and reveals a regional pattern of injury and intramuscular collagen which may correspond to variations in diaphragm loading.

Analysis of Variance↗

Accommodative intraocular lenses for age-related cataracts.

The standard intraocular lens (IOL) that is used to replace a cataractous lens cannot change focus from distant to near objects, so most patients need glasses for near vision after cataract surgery. Limited evidence suggests that accommodative IOLs provide better near vision than monofocal IOLs, but not better than multifocal IOLs. Long-term follow-up is needed to confirm patient outcomes, and determine whether the benefits justify the additional cost.

Accommodation, Ocular↗

Hot techniques for tonsillectomy.

(1) Some patients experience pain and bleeding after a standard or extracapsular tonsillectomy. (2) Evidence suggests that none of the hot tonsillectomy techniques offers concurrent reductions in intra- and post-operative bleeding and pain, compared with traditional cold-steel dissection with packs or ties. (3) Little information is available on the cost effectiveness of the hot techniques. (4) Diathermy is likely to remain the most commonly practised hot tonsillectomy technique.

Adenoidectomy↗

Effects of ion motion in intense beam-driven plasma wakefield accelerators.

Recent proposals for using plasma wakefield accelerators (PWFA) as a component of a linear collider have included intense electron beams with densities many times in excess of the plasma density. The beam's electric fields expel the plasma electrons from the beam path to many beam radii in this regime. We analyze here the motion of plasma ions under the beam fields, and find for a proposed PWFA collider scenario that the ions completely collapse inside of the beam. Simulations of ion collapse are presented. Implications of ion motion on the feasibility of the PWFA-based colliders are discussed.

Journal Article↗

Unmet need for recommended preventive health services among clients of California syringe exchange programs: implications for quality improvement.

BACKGROUND: Comprehensive preventive services are recommended for injection drug users (IDU), including screening tests, vaccinations, risk reduction counseling, and sterile syringes. Syringe exchange programs (SEP) may facilitate receipt of preventive services by IDUs, but whether SEP clients receive recommended preventive care is not known. We examined use of recommended preventive services by clients of 23 SEPs throughout California. METHODS: Five hundred and sixty SEP clients were recruited from 23 SEPs throughout California between March and September 2003. Receipt of 10 recommended preventive services and source of care (SEP versus non-SEP providers) was ascertained from client interviews. RESULTS: On average, SEP clients received only 13% of recommended preventive services and 49% of clients received none of the recommended services. Of services that were received, 76% were received from SEPs. In multivariate analysis, use of drug treatment and more frequent SEP visits were associated with receipt of recommended preventive services by clients. CONCLUSIONS: SEPs are often the only source of preventive care for their IDU clients. Still, SEP clients fail to receive most recommended preventive services. Interventions to increase use of preventive services and improve the quality of preventive care received by IDUs, such as increased access to drug treatment and SEPs, are needed.

California↗

Chromosomal assignment of the canine melanophilin gene (MLPH): a candidate gene for coat color dilution in Pinschers.

Pinschers affected by coat color dilution show a specific pigmentation phenotype. The dilute pigmentation phenotype leads to a silver-blue appearance of the eumelanin-containing fur and a pale sandy color of pheomelanin-containing fur. In Pinscher breeding, dilute black-and-tan dogs are called "blue," and dilute red or brown animals are termed "fawn" or "Isabella fawn." Coat color dilution in Pinschers is sometimes accompanied by hair loss and a recurrent infection of the hair follicles. In human and mice, several well-characterized genes are responsible for similar pigment variations. To investigate the genetic cause of the coat color dilution in Pinschers, we isolated BAC clones containing the canine ortholog of the known murine color dilution gene Mlph. RH mapping of the canine MLPH gene was performed using an STS marker derived from BAC sequences. Additionally, one MLPH BAC clone was used as probe for FISH mapping, and the canine MLPH gene was assigned to CFA25q24.

Animals↗

Automatic external defibrillators--time for a change?

Defibrillation is the definitive treatment for cardiac arrest. Until relatively recently the use of defibrillators was restricted to medical staff and paramedics. The development of automatic external defibrillators (AEDs) now means that this life-saving equipment may be used by anyone with a short period of training. This article will review the patho-physiology of cardiac arrest, the use of AEDs and their significance to the dental team. A medical emergency could happen at any time in the dental practice. Cardiac arrest is the most serious emergency that can occur. Whilst life-threatening incidents are very rare, the dental team requires to be trained in the management of a cardiac arrest.

Cardiopulmonary Resuscitation↗

Natural history of cardiac involvement in geleophysic dysplasia.

Geleophysic dysplasia is an autosomal recessive short-limbed, dysmorphic syndrome. The condition is frequently associated with cardiac valvular disease, which may result in secondary hypertrophy and cardiac failure. We describe two distantly related Pakistani children with classical features of geleophysic dysplasia. Pulmonary stenosis was recognized in both within a few months of birth. The younger child shows no signs of cardiac decompensation at the age of 7 years whilst her older cousin has developed a significant pulmonary gradient requiring surgical intervention in the second decade of life. The natural history of his disorder highlights that the cardiac involvement seen in apparently stable forms of geleophysic dysplasia is frequently progressive.

Child↗

Does a central MHC gene in linkage disequilibrium with HLA-DRB1*0401 affect susceptibility to type 1 diabetes?

Subtypes of HLA-DR4 are associated with susceptibility or protection against type 1 diabetes (T1DM). We addressed whether this reflects linkage disequilibrium with the true susceptibility locus by studying broader MHC haplotypes marked by alleles of HLA-B, IKBL (adjacent to TNFA) and complement C4. The study used a largely Caucasian cohort from Western Australia. HLA-DRB1*0401 and HLA-DRB1*0405 marked susceptibility to T1DM. In Caucasians, DRB1*0401 occurs predominantly in the 44.1 ancestral haplotype (AH; HLA-A2,B44, DRB1*0401,DQB1*0301) and the 62.1AH (HLA-A2,B15(62),DRB1*0401,DQB1*0302). HLA-B15 marked susceptibility and HLA-B44 marked with resistance to T1DM in patients and controls preselected for HLA-DRB1*0401. A gene between TNFA and HLA-B on the 8.1AH (HLA-A1,B8,;DR3,DQ2) modifies the effects of the class II alleles. Here, alleles characteristic of the 62.1AH (C4B3, IKBL+446*T and HLA-A2,B15) were screened in donors preselected for HLA-DRB1*0401. C4B3 was associated with diabetes, consistent with a diabetes gene telomeric of MHC class II. However, increases in carriage of IKBL+446*T and HLA-A2,B15 were marginal, as too few control subjects were available with the diabetogenic alleles. However, with these tools, selection of HLA-DRB1*0401, DQB1*0302 donors who are positive and negative for C4B3 will allow bidirectional mapping of diabetes genes in the central MHC.

Adolescent↗

Bacteriophage therapy to reduce Campylobacter jejuni colonization of broiler chickens.

Colonization of broiler chickens by the enteric pathogen Campylobacter jejuni is widespread and difficult to prevent. Bacteriophage therapy is one possible means by which this colonization could be controlled, thus limiting the entry of campylobacters into the human food chain. Prior to evaluating the efficacy of phage therapy, experimental models of Campylobacter colonization of broiler chickens were established by using low-passage C. jejuni isolates HPC5 and GIIC8 from United Kingdom broiler flocks. The screening of 53 lytic bacteriophage isolates against a panel of 50 Campylobacter isolates from broiler chickens and 80 strains isolated after human infection identified two phage candidates with broad host lysis. These phages, CP8 and CP34, were orally administered in antacid suspension, at different dosages, to 25-day-old broiler chickens experimentally colonized with the C. jejuni broiler isolates. Phage treatment of C. jejuni-colonized birds resulted in Campylobacter counts falling between 0.5 and 5 log10 CFU/g of cecal contents compared to untreated controls over a 5-day period postadministration. These reductions were dependent on the phage-Campylobacter combination, the dose of phage applied, and the time elapsed after administration. Campylobacters resistant to bacteriophage infection were recovered from phage-treated chickens at a frequency of <4%. These resistant types were compromised in their ability to colonize experimental chickens and rapidly reverted to a phage-sensitive phenotype in vivo. The selection of appropriate phage and their dose optimization are key elements for the success of phage therapy to reduce campylobacters in broiler chickens.

Animals↗

High strain mechanical loading rapidly induces tendon apoptosis: an ex vivo rat tibialis anterior model.

BACKGROUND: The role of apoptosis, or programmed cell death, has only recently been explored in tendon. OBJECTIVE: To investigate the development of apoptosis after high strain loading of rat tendon. METHODS: The right tibialis anterior tendons of three rats were prepared for mechanical loading, and left tendons were prepared identically as non-loaded controls. Tendon was loaded with 20% strain for six hours using a 1 Hz longitudinal sine wave signal. The following were used to assess apoptosis: (a) a monoclonal mouse antibody (F7-26) to label single stranded DNA breaks; (b) a rabbit polyclonal antibody that specifically recognises the cleaved form of caspase-3. RESULTS: Light microscopy confirmed that the high strain protocol induced a stretch overload injury. Control tendons showed little or no staining with the F7-26 antibody, but the loaded tendons displayed numerous apoptotic cells. The percentage of apoptotic cells (20%) in the loaded tendon was significantly greater than in the control tendon (1%) (p = 0.000). The labelled cells colocalised with abnormal nuclear morphology, including nuclear fragmentation. The staining against cleaved caspase-3 was positive in loaded tendons only, and localised both to nucleus and cytoplasm. CONCLUSION: This experiment extends knowledge of human tendon apoptosis by showing that apoptosis can occur in response to short term, high strain mechanical loading. This is the first report of mechanical loading of intact tendon causing excessive apoptosis.

Animals↗

Are routine breast and pelvic examinations necessary for women starting combined oral contraception?

Millions of women worldwide use combined oral contraception (COC). Most of them are in good health and have no contraindications to using any contraceptive method. Although extremely safe for the vast majority of women and even though the absolute risk of complications is very small, COC is associated with an increased relative risk of serious conditions including cardiovascular disease and breast and cervical cancer. In many countries, breast and pelvic examinations are routinely undertaken annually for all women using hormonal contraception. Breast and pelvic examination have low detection rates for abnormality and may yield clinically irrelevant results, causing anxiety and inconvenience to the patient for no obvious gain. There is no good evidence to support routine breast or pelvic examination either for women starting hormonal contraception or for monitoring long-term use.

Breast↗

The national survey of adverse reactions to dental materials in the UK: a preliminary study by the UK Adverse Reactions Reporting Project.

OBJECTIVE: Dental treatment involves the use of a wide range of materials. Many of the dental materials or their components pose a potential risk to the patient and member of the dental team. Pre-market biocompatibility testing cannot guarantee absolute safety, making monitoring of materials likely to cause an adverse reaction essential. The prevalence of adverse reactions to dental materials amongst dental patients and staff has not been systematically monitored in the UK. This project aims to develop a systematic approach to the evaluation and monitoring of the extent and severity of adverse reactions to dental materials in the UK. METHOD: Through the distribution of reporting forms to dental surgeries and laboratories in the UK, the ARRP has received 1,075 complete reports relating to adverse reactions seen or experienced by dental staff and patients. RESULTS: The main findings were that different materials cause adverse reactions to different groups of people. The largest proportion of patient related adverse reactions were reported to be due to metals (n = 175). These were mainly amalgam associated oral lichenoid reactions (n = 124). Dental technicians reported acrylic resin as the causal factor of hand dermatitis in 61% (44 out of a total 72) of cases reported. Finally, dental surgery staff reported gloves as causing hand dermatitis in 75% of cases (398 out of a total 531). CONCLUSIONS: Different dental materials affect different person groups depending on their exposure to the material. Dental staff are most at risk from an adverse reaction to latex gloves, whereas most reported reactions for patients were due to metals. For dental technicians the biggest danger of an adverse reaction was from acrylic resins. There is a need to continue to raise the awareness among dental professionals of the existence of the Adverse Reactions Reporting Project so as to overcome problems of under-reporting.

Acrylic Resins↗