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Biomedical subjects

J W Ferguson

Publications and source records attributed to J W Ferguson.

At least 19 recordsLinked to original sources

Review article: recent advances in the management of bleeding gastric varices.

Gastric variceal bleeding can be challenging to the clinician. Tissue adhesives can control acute bleeding in over 80%, with rebleeding rates of 20-30%, and should be first-line therapy where available. Endoscopic ultrasound can assist in better eradication of varices. The potential risks of damage to equipment and embolic phenomena can be minimized with careful attention to technique. Variceal band ligation is an alternative to tissue adhesives for the management of acute bleeding, but not for secondary prevention due to a higher rate of rebleeding. Endoscopic therapy with human thrombin appears promising, with initial haemostasis rates typically over 90%. The lack of controlled studies for thrombin prevents universal recommendation outside of clinical trials. Balloon occluded retrograde transvenous obliteration is a recent technique for patients with gastrorenal shunts, although its use is limited to clinical trials. Transjugular intrahepatic portosystemic stent shunt is an option for refractory bleeding and secondary prophylaxis, with uncontrolled studies demonstrating initial haemostasis obtained in over 90%, and rebleeding rates of 15-30%. Non-cardioselective beta-blockers are an alternative to transjugular intrahepatic portosystemic stent shunt for secondary prophylaxis, although the evidence is limited. Shunt surgery should be considered in well-compensated patients. Splenectomy or embolization is an option in patients with segmental portal hypertension.

Catheterization↗

Endothelin-1 contributes to maintenance of systemic but not portal haemodynamics in patients with early cirrhosis: a randomised controlled trial.

BACKGROUND AND AIMS: Increased endothelin (ET)-1 activity may contribute to the complications of cirrhosis and portal hypertension. The aim of this study was to assess the systemic and portal haemodynamic effects of selective ET-A and ET-B receptor antagonism in patients with cirrhosis. METHODS: Sixteen patients with cirrhosis and portal hypertension (aged 52 (1) years, Pugh score 6.2 (0.3)) underwent 24 studies with infusions of: (A) selective ET-A antagonist, BQ-123 (n = 8), at 1000 and 3000 nmol/min; (B) selective ET-B antagonist, BQ-788 (n = 8), at 100 and 300 nmol/min; or (C) matched saline placebo (n = 8) in a double blind randomised manner. Haemodynamic measurements were performed through pulmonary artery, hepatic venous, and femoral artery catheters. RESULTS: Baseline patient characteristics were well matched. Compared with placebo, BQ-123 decreased mean arterial pressure (MAP -15 (11) mm Hg (-18%); p<0.02) and pulmonary vascular resistance index (PVRI -81 (54) dyn x s x m2/cm5 (-64%); p<0.05), with no effect on hepatic venous pressure gradient (HVPG), cardiac index (CI), or systemic vascular resistance index (SVRI). Compared with placebo, BQ-788 increased MAP (+11 (3) mm Hg (+12%); p<0.03) and SVRI (+1101 (709) dyn x s x m2/cm5 (+50%); p<0.05), reduced CI (-1.0 (0.4) l/min/m2 (-29%); p = 0.05) with no effect on HVPG or PVRI. CONCLUSIONS: ET-1 contributes to maintenance of systemic and pulmonary haemodynamics without acutely affecting HVPG in patients with early cirrhosis. In this group of patients, the use of selective ET-A and ET-B antagonists for the management of variceal haemorrhage is likely to be limited.

Adult↗

Inducible nitric oxide synthase activity contributes to the regulation of peripheral vascular tone in patients with cirrhosis and ascites.

BACKGROUND: Overexpression of inducible nitric oxide synthase (iNOS) and increased nitric oxide generation may be associated with the hyperdynamic circulation of patients with cirrhosis. We have, for the first time, used the highly selective iNOS inhibitor, 1400W, to determine whether iNOS activity contributes to the regulation of vascular tone in patients with cirrhosis and ascites. METHODS: Bilateral forearm blood flow was measured using strain gauge plethysmography in eight patients with cirrhosis and ascites, and eight matched healthy volunteers during intrabrachial infusion of 1400W (0.1-1 micromol/min), N(G)-monomethyl-L-arginine (L-NMMA, a non-selective NOS inhibitor; 2-8 micromol), and norepinephrine (a control vasoconstrictor; 60-480 pmol/min). RESULTS: In patients with cirrhosis, 1400W, L-NMMA, and norepinephrine caused dose dependent reductions in forearm blood flow: peak reductions of 11 (5)%, 37 (4)%, and 48 (5)%, respectively (p < 0.05 for all). In contrast, 1400W had no effect on blood flow (+4 (8)%; NS) in healthy controls despite similar reductions in blood flow with L-NMMA and norepinephrine (39 (5)% and 49 (5)%, respectively; p < 0.05 for both). CONCLUSIONS: We have, for the first time, demonstrated that 1400W causes peripheral vasoconstriction in patients with cirrhosis but not healthy matched controls. This suggests that iNOS contributes to the regulation of peripheral vascular tone in patients with cirrhosis and ascites, and may contribute towards the hyperdynamic circulation associated with this condition.

Ascites↗

The Palmer notation system and its use with personal computer applications.

The arguments for and against the Palmer dental notation system are briefly discussed, including the perceived difficulty of reproducing this on personal computers. Some technical solutions to the problems encountered in everyday Windows-based programs are outlined, with suggestions as to possible future applications.

Computer Communication Networks↗

Treatment outcomes for adolescent ectodermal dysplasia patients treated with dental implants.

UNLABELLED: To evaluate dental implant survival in patients with ectodermal dysplasia (ED). To assess patterns of hypodontia in this patient group. METHOD: . A retrospective analysis of the use of dental implants in ED patients treated at the Royal Children's Hospital, Melbourne. RESULTS: Sixty-one implants were placed into 14 patients (nine male and five female). The mean age of patients receiving maxillary implants was 18 years 6 months (range 17 years 9 months-20 years 0 months) and mandibular implants was 17 years 5 months (range 12 years 2 months-21 years 11 months). The mean follow-up period was 3 years 4 months (range 1 year 18 months-5 years 1 month). Forty-three implants were placed in the anterior mandible, three in the posterior mandible and the remaining 15 in the anterior maxilla. Of the 61 implants placed, 54 [88.5%] successfully integrated and were able to be restored. Three of the 15 implants placed into the anterior maxilla [20%] failed, while four of the 46 in the anterior mandible failed [8.7%]. Five of the 14 patients [35.7%] had at least one implant fail prior to abutment connection. At the 12-month review appointments, 41 of the integrated 54 implants [76%] were reviewed and classed as successful, giving an overall success at follow up of 67.2%. Thirteen implants [21.3%] were unable to be reviewed owing to geographical reasons. Teeth most likely to be present in the maxilla were the central incisors [71%], first molars [54%] and canines [43%], whereas in the mandible they were the canines [53%] and the first premolars and first molars [40%]. CONCLUSIONS: Dental implants can be placed, restored and loaded in ED patients. Maxillary teeth most likely to be present are the central incisors, canines and first molars, whereas in the mandible the canines, first premolars and molars are most likely to be present. Prior to cessation of growth, implant placement in the symphyseal region of the anterior mandible may be performed with caution. Despite the limited numbers and with due consideration to jaw development, the results support the continual use of endosseous dental implants in this group of patients for optimal clinical outcomes.

Adolescent↗

Steroid cover for dental patients on long-term steroid medication: proposed clinical guidelines based upon a critical review of the literature.

Based to a great extent upon mainly anecdotal case reports and theory, there is a general acceptance that patients on long-term systemic steroid medication should receive supplementary glucocorticoids or "steroid cover" when undergoing certain types of stressful treatment including dentistry. The theoretical basis to this practice is that exogenous steroids suppress adrenal function to an extent that insufficient levels of cortisol can be produced in response to stress, posing the risk of acute adrenal crisis with hypotension and collapse. The purpose of this paper is to review relevant literature and propose clinical guidelines for dental practitioners. Of numerous reported cases of adrenal crisis following procedural interventions, few stand up to critical evaluation. Other reviewers have reached similar conclusions. A number of studies confirm the low likelihood of significant adrenal insufficiency even following major surgical procedures. Various authors have suggested modified guidelines for management of patients on steroid medications. Patients on long-term steroid medication do not require supplementary "steroid cover" for routine dentistry, including minor surgical procedures, under local anaesthesia. Patients undergoing general anaesthesia for surgical procedures may require supplementary steroids dependent upon the dose of steroid and duration of treatment.

Acute Disease↗

Latex allergy in dentistry. Review and report of case presenting as a serious reaction to latex dental dam.

Latex allergy may have severe consequences including development of anaphylaxis. This report describes a patient who underwent a reaction to latex dental dam manifesting as erythema, facial swelling and mild airway compromise. Restorative procedures under latex dental dam were performed under local anaesthesia on two occasions resulting in reactions of increasing severity. Following the first event the cause of the reaction was undetermined, but attributed to a possible allergy to local anaesthetic, and managed with corticosteroids and antihistamines. On a subsequent occasion the swelling was more severe, associated with difficulty in swallowing and mild airway compromise, and was managed as previously with adrenaline also being required. Latex allergy was subsequently confirmed.

Aged↗

Management of unerupted maxillary canines where no orthodontic treatment is planned; a survey of UK consultant opinion.

OBJECTIVE: To assess current consultant opinion on the management of impacted maxillary canines in patients for whom no orthodontic treatment is planned. DESIGN: Questionnaire survey. METHOD: Questionnaires were sent to all UK consultant orthodontists identified from the Consultant Orthodontists Group database. Follow-up questionnaires were sent to those who had not replied within 6 weeks. An overall response rate of 76% was achieved. RESULTS: Most consultants were in favor of intervention, with removal of the unerupted canine, although a significant minority suggested a conservative approach. Of the latter group, nearly all recommended radiographic monitoring, but there was little agreement regarding the frequency and duration of this. The risk of root resorption was stated to be the most important factor justifying monitoring. CONCLUSIONS: Significant variation was found amongst UK consultant orthodontists with regard to the management of impacted canines, where orthodontic treatment was not planned. The clinical and radiographic features, which the respondents stated would influence their decision to remove or leave the canine, were not those that existing research suggests as being the primary risk factors. It is suggested that, once the patient has passed the peak age for initiation of resorption, a more conservative approach may be appropriate.

Attitude of Health Personnel↗

Review article: the management of acute variceal bleeding.

Variceal haemorrhage is a common medical emergency with a high mortality (30-50%). Adequate resuscitation is vital, and once stabilised the patient should be moved to a high-dependency area. Antibiotics reduce mortality, and the vasoactive drug terlipressin should be administered if early endoscopy is unavailable. Early endoscopy is essential both to make the diagnosis and to allow therapeutic measures to be performed. The evidence suggests that variceal band ligation is the most effective therapy for oesophageal varices. If gastric varices are found at the index endoscopy the evidence at present is inadequate to be certain which is the best treatment, but both endoscopic therapy with cyanoacrylate or thrombin and transjugular intrahepatic portosystemic stent shunt (TIPSS) have been reported to be of benefit. When initial treatments fail, rescue therapy should be initiated. Most authorities agree that TIPSS is the rescue therapy of choice. Many questions remain concerning the treatment of acute variceal bleeding, particularly the ideal therapy for gastric varices and the role of combination vasoactive and endoscopic therapy. Randomised controlled trials are required to answer these important issues.

Acute Disease↗

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Fees and Charges↗

Acute leukaemia presenting as oral ulceration to a dental emergency service.

Leukaemia is a neoplastic disease characterized by an excessive proliferation of immature white blood cells and their precursors. Oral lesions may be the presenting feature of acute leukaemias, which can be rapidly fatal if left untreated. This report describes the case of a 22-year-old female who presented to a dental emergency department with oral manifestations of acute leukaemia. It outlines the role of oral lesions in the diagnosis of acute leukaemias and emphasizes the importance of immediate referral by general dental practitioners.

Acute Disease↗

Effectiveness of intracanal irrigants and medications against the yeast Candida albicans.

An in vitro study was conducted to determine the susceptibility of the yeast Candida albicans to various intracanal irrigants and medications. The minimum inhibitory concentration (MIC) of sodium hypochlorite, hydrogen peroxide, chlorhexidine digluconate, and aqueous calcium hydroxide that is required to kill a standardized inoculum of C. albicans was determined. Growth of the yeast was measured by optical density. Sodium hypochlorite, hydrogen peroxide, and chlorhexidine digluconate were effective anticandidal agents with MICs of <10 microgram/ml, 234 microgram/ml, and <0.63 microgram/ml, respectively. Aqueous calcium hydroxide had no activity. A standardized inoculum of C. albicans cells was also placed in direct contact with either calcium hydroxide paste or camphorated para-monochlorophenol (CPMC), and candidal growth was assessed by colony counts on Sabouraud's dextrose agar. Calcium hydroxide paste and CPMC, when maintained in direct contact with C. albicans, were effective antifungal agents.

Analysis of Variance↗

Current concepts in the management of oral squamous cell carcinoma.

This paper focuses on how patients with oral squamous cell carcinoma (SCC) are assessed and managed once they have been referred for specialist care. Current and future treatment options are presented and basic management principles are discussed. It is our hope that this will enable the general dental practitioner to gain insight into the process and reasoning behind the multidisciplinary treatment of these complex cases.

Carcinoma, Squamous Cell↗

Empirical evaluation of preservation methods for faecal DNA.

We evaluate the relative effectiveness of four methods for preserving faecal samples for DNA analysis. PCR assays of fresh faecal samples collected from free-ranging baboons showed that amplification success was dependent on preservation method, PCR-product size, and whether nuclear or mitochondrial DNA was assayed. Storage in a DMSO/EDTA/Tris/salt solution (DETs) was most effective for preserving nuclear DNA, but storage in 70% ethanol, freezing at -20 degrees C and drying performed approximately equally well for mitochondrial DNA and short (< 200 bp) nuclear DNA fragments. Because faecal DNA is diluted and degraded, repeated extractions from faeces may be necessary and short nuclear markers should be employed for genotyping. A review of molecular scatology studies further suggests that three to six faeces per individual should be collected.

Animals↗

Acute oral toxicity study of pyridostigmine bromide, permethrin, and DEET in the laboratory rat.

This study investigated the lethal interaction of pyridostigmine bromide (PB), permethrin, and DEET when given to adult male rats by gavage and was separated into two phases. Phase I determined the acute oral lethal dose-response relationship of each compound with the vehicle, propylene glycol. Phase II was divided into two portions: a dose-response study using probit units obtained from phase I [lethal dose (LD) 16, 30, 50, 70, and 84], and an interaction study that contained low levels (calculated LD16, additive LD32) of the two compounds while the concentration of the third compound was varied. Rats were fasted overnight, dosed, and observed for 14 d. A significant increase in lethality occurred when PB, permethrin, and DEET were given concurrently when compared to expected additive values. Furthermore, solutions containing PB and permethrin or PB and DEET also caused a significant increase in lethality when compared to expected additive values. This information suggests that lethality in this study was more than an additive effect.

Animals↗

Eruption of palatal canines following surgical exposure: a review of outcomes in a series of consecutively treated cases.

The records of a consecutive series of 72 patients who had undergone excisional exposure of one or both palatally displaced canines were reviewed. The purpose was to ascertain whether the canine(s) erupted spontaneously following surgery, whether orthodontically-assisted eruption was required or whether the procedure failed completely indicating the need for re-exposure. The results of the study suggest that the majority of canines will erupt once exposed and of those that fail to erupt completely most will still remain exposed to a sufficient extent to allow attachments to be bonded to the palatal surface.

Adolescent↗