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Biomedical subjects

D J Moore

Publications and source records attributed to D J Moore.

At least 19 recordsLinked to original sources

Foreign body complications of central venous catheterisation in critically ill patients.

In three critically ill patients, central venous catheter--associated foreign bodies were identified while the patients were in the intensive care unit. Two patients had fragments of retained catheter; in the third patient a guide-wire was lost within the vascular tree. The catheter fragments were associated with clinical symptoms while side effects were not observed with loss of the guide-wire. All three foreign bodies were removed without complications.

Catheterization, Central Venous

Comparison of the physical properties of two types of polydimethyl siloxane for fabrication of facial prostheses.

The in vitro physical properties of two types of polydimethyl siloxane, MDX 4-4210 and a new material A-2186, were compared. The properties that were investigated in this study were tensile strength, elongation, tear strength, and surface hardness. The properties tested were selected because of their clinical significance for fabricating a facial prosthesis. According to the results obtained in this investigation, the new material, A-2186, had greater tear resistance, tensile strength, and a larger percentage of elongation. A-2186 material, also proved to be softer at the surface than the MDX 4-4210. This combination of physical properties makes this material, A-2186, a better choice than the traditional MDX 4-4210 for the fabrication of facial prostheses.

Biocompatible Materials

Asymptomatic carotid stenosis: a benign lesion?

Recent reports of the risk of asymptomatic carotid stenosis have been compromised by flawed patient selection or the performance of a large number of carotid endarterectomies during follow-up. We report the natural history of a randomly selected group of asymptomatic patients (n = 188; 114 males and 74 females) with documented carotid artery disease who were prospectively followed without intervention for up to 8 years. Risk factors included ischaemic heart disease in 17%, diabetes in 10%, hypertension in 46% and 88% were smokers. The degree of internal carotid stenosis was classified by duplex scanning and a total of 259 vessels had evidence of atherosclerosis. Study end-points included TIA, CVA and death. At mean follow-up of 4 years 3% of the 96 patients with internal carotid artery stenosis of less than 50% had died and 2% suffered a stroke. Six per cent of patients with a stenosis of 50-79% had died and 4% and 2% had suffered a CVA and TIA, respectively. In the 59 patients with greater than 80% stenosis 7% had suffered a TIA and an additional 7% a CVA, while 2% had died. None of the patients suffering a stroke had an antecedent TIA. Though the incidence of ischaemic events is significantly higher in patients with greater than 80% stenosis the incidence of unheralded stroke remains low. We therefore continue to recommend a conservative approach to the management of asymptomatic carotid stenosis.

Aged

The common bilio-pancreatic channel syndrome in childhood.

An abnormally long common bilio-pancreatic channel has been found in association with choledochal cysts and biliary strictures in childhood. It may also present with recurrent abdominal pain, vomiting, hyperamylasaemia and jaundice. This has been termed the common channel syndrome (CCS). Two cases with the CCS presenting early in childhood are reported together with a review of the literature. Open sphincteroplasty was performed in both cases with a satisfactory outcome.

Child

Decline of exocrine pancreatic function in cystic fibrosis patients with pancreatic sufficiency.

Patients with cystic fibrosis and pancreatic sufficiency were investigated for evidence of progressive pancreatic disease. From a cohort of 630 patients, 20 pancreatic-sufficient patients became pancreatic insufficient after an average duration of 5.6 y (range 0.6-20.6 y) from diagnosis. Among 54 patients documented to be pancreatic sufficient by direct pancreatic stimulation test, 47 remained pancreatic sufficient and seven developed pancreatic insufficiency. The patients who ultimately developed pancreatic insufficiency were younger and had greatly reduced outputs of enzyme, fluid, and electrolytes. Those who remained pancreatic sufficient showed enzyme secretion close to or within the non-cystic fibrosis control range. Twenty of these patients underwent a second pancreatic stimulation test after an average interval of 4 y (range 1.3-6.2 y). No significant alteration in enzyme, fluid, or electrolyte output was seen in the patients who remained pancreatic sufficient, but there was further reduction in enzyme and fluid output in the patients who developed pancreatic failure. In conclusion, the majority of pancreatic-sufficient patients with pancreatic enzyme secretion within the control range showed no deterioration of function over an extended time period. However, a small number of pancreatic-sufficient patients with reduced enzyme and fluid secretion are at risk of pancreatic failure.

Adolescent

Hypodipsic hypernatraemia in a miniature schnauzer.

Normovolaemic hypernatraemia as a result of a suspected congenital primary hypodipsia was diagnosed in a young male Miniature Schnauzer. Despite an elevated serum sodium concentration, the dog did not appear dehydrated on physical examination and the urine osmolality: plasma osmolality ratio was greater than 4; antidiuretic hormone deficiency was therefore not suspected. Basal serum cortisol and thyroxine concentrations were normal. Plasma aldosterone concentration and plasma renin activity (37 pmol l-1 and 1.55 ng dl-1 h-1 respectively) were within normal range. A defective central thirst regulation mechanism was suspected as the dog was totally disinterested in drinking water despite the chronically elevated serum sodium concentration. Excessive ingestion of water mixed with food, and milk resulted in hyponatraemia and associated cerebral oedema. On stabilisation of the dog's condition, a calculated fluid intake based on daily maintenance fluid requirements was prescribed to prevent recurrence of hypernatraemia and hyponatraemia, and associated signs of central nervous system disease. The dog was in apparent good health with controlled fluid intake when examined 230 d later.

Animals

The profunda femoris: a durable outflow vessel in aortofemoral surgery.

Aorta-common femoral artery bypass is the standard operation for relief of aortoiliac occlusive disease. When extensive superficial femoral artery disease coexists, the profunda femoris, even in its distal portion, may be used as the outflow vessel. To test this assumption we compared cumulative patency, limb salvage, and the need for distal bypass of 134 aorta-profunda femoris and 151 aorta-common femoral artery bypasses performed consecutively for aortoiliac occlusive disease over a 12-year period. We also analyzed results of proximal (n = 103) and distal (n = 31) aortoprofunda bypasses. Angiographic and noninvasive studies showed greater disease in limbs undergoing aorta-profunda femoris bypass. However, no difference was observed in cumulative patency (91% +/- 6% vs 96% +/- 3%) or limb salvage (90% +/- 6% vs 94% +/- 3%) at 5 years. Seventeen distal bypasses in the group undergoing profunda femoris bypass and 20 distal bypasses in the group undergoing common femoral artery bypass were required to maintain limb salvage. Proximal and distal aorta-profunda femoris bypasses showed no difference in cumulative patency (91% +/- 9% vs 95% +/- 6%) or limb salvage (94% in each group) at 3 years. Standard aorta-common femoral artery and aorta-profunda femoris bypass provide cumulative patency and limb salvage exceeding 90% at 5 years; concomitant or subsequent distal bypass was required in 12% or limbs undergoing aorta-profunda femoris bypasses. Both proximal and distal profunda femoris arteries provide a durable outflow tract when aortoiliac and femoropopliteal occlusive disease are combined.

Aged

The murine adenosine deaminase promoter requires an atypical TATA box which binds transcription factor IID and transcriptional activity is stimulated by multiple upstream Sp1 binding sites.

We have explored the template and factor requirements for in vitro transcription of the GC-rich promoter of the murine adenosine deaminase gene. The core promoter consists of an A-rich sequence (TAAAAAA) 27 base pairs upstream of the initiation site which binds transcription factor IID (TFIID) and a high affinity Sp1 binding site located 27 base pairs further upstream. Multiple upstream elements increased core promoter activity 20-fold and correspond to protected regions in DNase I footprinting assays with purified Sp1 protein. Internal deletion of the TA6 element alone eliminated transcription in spite of the presence of all other promoter elements including four Sp1 binding sites. Recombinant human TFIID supported weak basal transcription in heat-treated nuclear extracts whereas a partially purified TFIID fraction from HeLa cells reconstituted a maximal level of transcription. Inclusion of 12 base pairs immediately adjacent to the proximal Sp1 site resulted in a 5-fold boost in transcriptional activity and corresponds to a second Sp1 binding site. These results serve as a basis for further exploration of the factors involved in the developmental and selective high level tissue expression of the murine adenosine deaminase gene.

Adenosine Deaminase

Infrainguinal polytetrafluoroethylene grafts: saved limbs or wasted effort? A report on ten years' experience.

Two-hundred and twenty-four infrainguinal polytetrafluoroethylene reconstructions were performed for critical ischemia over a 10 year period: 48 to the above-knee popliteal artery, 113 to the below-knee popliteal artery, and 63 to the tibial vessels. The cumulative patency rates were 84 +/- 6% and 63 +/- 9% for above-knee popliteal, 53 +/- 5% and 35 +/- 7% for below-knee popliteal, 45 +/- 6% and 30 +/- 9% for tibial vessels at one and five years respectively. Limb salvage rates were 81 +/- 6% and 73 +/- 9% (above-knee popliteal), 69 +/- 5% and 57 +/- 9% (below-knee popliteal), 64 +/- 7% and 32 +/- 10% (tibial vessels) at one and five years respectively. Graft occlusion did not result in limb loss in 32 cases. Preoperatively, 54% of the patients had limited mobility while 43% were regarded as severely restricted. At follow-up, 57% of the patients were considered to be independent, 26% had limited mobility, and 17% were still severely restricted. Polytetrafluoroethylene provides good short-term limb salvage and improved mobility in patients with critical ischemia and poor life expectancy. Its use is well worth the effort.

Activities of Daily Living

Upper limb embolus: a timely diagnosis.

In a ten year period, 36 patients were treated surgically for embolic occlusion of upper limb vessels. The sources of embolus were cardiac (58%), peripheral aneurysm (22%) and unknown (20%). Brachial embolectomy was performed in all cases. Six out of eight peripheral aneurysms were resected. A patency rate of 94% was achieved at five years. Hospital mortality and morbidity rates were 3% and 10%, respectively. One patient died of a myocardial infarct one week postoperatively. Three patients suffered ischemic contracture or amputation; all three presented after 36 hours. We conclude that upper limb emboli are usually easy to recognize and treat. Prompt surgery (less than 24 hours) produces the most satisfactory results. Late presentation or delay in treatment can result in limb loss.

Acute Disease

Stereophotogrammetric analysis of abutment tooth movement in distal-extension removable partial dentures with intracoronal attachments and clasps.

This study applied the three-dimensional measurement technique of stereophotogrammetry to measure abutment tooth movement under occlusal loading as a function of intracoronal attachment and clasp design. Six distal-extension removable partial denture designs were studied: (1) RPI-mesial occlusal rest, proximal plate, buccal I-bar; (2) cast circumferential clasp; (3) P.D. locking semiprecision attachment; (4) Thompson dowel nonlocking semiprecision attachment; (5) McCollum precision attachment; and (6) Stern G/L precision attachment. The movement in microns was determined by computer analysis. The Thompson dowel semiprecision attachment generated the most abutment movement in a gingival direction. The clasp-retained designs generally had less total movement than the attachment designs. Clasps and attachments for the abutment teeth adjacent to the distal-extension bases generally moved more than the abutment teeth.

Analysis of Variance

Organisation and expression of small subunit ribosomal RNA genes encoded by a 35-kilobase circular DNA in Plasmodium falciparum.

A restriction map of the 35-kb circular DNA molecule of Plasmodium falciparum showed that a region of about 6 kb, encoding both a large and a small subunit ribosomal RNA gene, has been duplicated in inverted orientation. The complete sequence of one small subunit rRNA gene is presented as well as an analysis of transcripts from erythrocytic stage parasites. Comparative sequence analysis of the rRNA gene and the proposed secondary structure of the rRNA suggest that it is of organellar origin. Intriguingly, while some characteristics of the small subunit rRNA gene are similar to mitochondrial sequences, others are more like those of plastids. The origin of the circular DNA molecule and evolutionary implications of its genetic content are discussed.

Animals

Histologic characteristics of carotid artery plaque.

Carotid plaque characteristics associated with the production of symptoms were identified with quantification of carotid plaque constituents in high-grade stenotic asymptomatic (n = 8) and symptomatic (n = 44) plaques. Asymptomatic plaques contained significantly more fibrous/collagen material (88%) than symptomatic plaques (66%) (p less than 0.05). Hemorrhage constituted 2% and 1% of asymptomatic and symptomatic plaques, respectively. The predominant nonfibrous material was a pink amorphous material mixed with cholesterol, which composed 7% of asymptomatic and 27% of symptomatic plaques (p less than 0.05). No relationship was found between plaque composition and the number of ipsilateral ischemic neurologic events, nor was there evidence of a healing process. B-mode ultrasound scanning had a sensitivity of 94% in identifying plaque with greater than 80% fibrous content. We believe that plaque composition may be a useful discriminating factor in selecting asymptomatic patients for carotid endarterectomy.

Arteriosclerosis

Anal size in children: the influence of age, constipation, rectal examination and defaecation.

With the increase in the number of reported cases of child abuse it is important that medical practitioners should know the normal values for the size of the anus. Children aged 3 months to 15 years, attending a paediatric gastroenterology clinic for a routine examination, had a photographic record made of the anus 30 seconds after exposure of the anus as part of a standardised examination protocol. Anorectal disease, including Crohn's disease was present in eight children. Analysis of the 54 children without anorectal disease indicated that the anteroposterior diameter of the anus was less than 10.0 mm and the transverse diameter was less than or equal to 2.0 mm. Age, sex of the child, digital rectal examination, time since last defaecation and the capacity and contents of the rectum were unrelated to the size of the anus. In view of the difficulties which arise in suspected child abuse, medical practitioners should gain experience of the normal appearance and size of the anus. This can best be validated within a medicolegal framework if some form of standardised examination protocol is used. The key element of such an examination is not the position in which the child is examined but the time taken to observe the anus, to allow any dynamic changes to occur. An inspection time of 30 seconds in a cooperating conscious child is recommended.

Adolescent