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K MacKenzie

Publications and source records attributed to K MacKenzie.

At least 37 records · Page 2Linked to original sources
PubMed2001

One-stop neck lump clinic: phase 2 of audit. How are we doing?

Regular monitoring and audit of a service are integral to ensuring maintenance of efficiency and standards. This is particularly important where the quality of the service is operator dependent, as is the case in the clinical diagnosis of neck lumps and fine needle aspiration cytology. The one-stop neck lump clinic has now been running in the department for more than 20 months. A previous article described the results of the first phase audit carried out at 6 months and had identified a waiting time to be seen that was longer than that recommended by the British Association of Otorhinolaryngologists, Head and Neck Surgeons. Measures were implemented to reduce this waiting time and a second audit was carried out after another 10 months with the aims of assessing if modification of the means of referral reduces waiting time and if the outcomes of clinical performance in phase 1 could be maintained or improved. We discuss the results of phase 2 in the audit spiral.

Adolescent↗
PubMed2001

Developing stochastic epidemiological models to quantify the dynamics of infectious diseases in domestic livestock.

A stochastic model describing disease transmission dynamics for a microparasitic infection in a structured domestic animal population is developed and applied to hypothetical epidemics on a pig farm. Rational decision making regarding appropriate control strategies for infectious diseases in domestic livestock requires an understanding of the disease dynamics and risk profiles for different groups of animals. This is best achieved by means of stochastic epidemic models. Methodologies are presented for 1) estimating the probability of an epidemic, given the presence of an infected animal, whether this epidemic is major (requires intervention) or minor (dies out without intervention), and how the location of the infected animal on the farm influences the epidemic probabilities; 2) estimating the basic reproductive ratio, R0 (i.e., the expected number of secondary cases on the introduction of a single infected animal) and the variability of the estimate of this parameter; and 3) estimating the total proportion of animals infected during an epidemic and the total proportion infected at any point in time. The model can be used for assessing impact of altering farm structure on disease dynamics, as well as disease control strategies, including altering farm structure, vaccination, culling, and genetic selection.

Animals↗
PubMed2001

Utilizing stochastic genetic epidemiological models to quantify the impact of selection for resistance to infectious diseases in domestic livestock.

This paper demonstrates the use of stochastic genetic epidemiological models for quantifying the consequences of selecting animals for resistance to a microparasitic infectious disease. The model is relevant for many classes of infectious diseases where sporadic epidemics occur, and it is a powerful tool for investigating the costs, benefits, and risks associated with breeding for resistance to specific diseases. The model is parameterized for transmissible gastroenteritis, a viral disease affecting pigs, and selection for resistance to this disease on a structured pig farm is simulated. Two genetic models are used, both of which involve selection of sires. The first involves selection with the assumption of continuous genetic variation (the continuous selection model). The second involves selection with the assumption of introgression of a major recessive gene that confers resistance (the gene introgression model). In the base population, the basic reproductive ratio, R0 (i.e., the expected number of secondary cases after the introduction of a single infected animal) was 2.24, in agreement with previous studies. The probabilities of no epidemic, a minor epidemic (one that dies out without intervention), and a major epidemic were 0.55, 0.20, and 0.25, respectively. Selection for resistance, under both genetic models, resulted in a nonlinear decline in the probability of a major epidemic and a decrease in the severity of the epidemic, should it occur, until R0 was less than 1.0, at which point the probability of a major epidemic was zero. For minor epidemics, the probability and severity of the epidemic increased until R0 reached 1.0, at which point the probabilities also fell to zero. The epidemic probabilities were critically dependent on the location on the farm where infected animals were situated, and the relative risks of different groups of animals changed with selection. The main difference between the two genetic models was in the time scale; the introgression results simply depended on how quickly the resistance allele could be introgressed into the population. For the introgression model, the probability of a major epidemic declined to zero when 0.6 of the animals were homozygous for the resistance allele.

Animal Husbandry↗
PubMed2000

Fine-needle aspiration cytology of salivary gland: a review of 341 cases.

Three hundred and forty-one salivary gland fine-needle aspiration (FNA) cytology specimens taken over a 6-yr period were reviewed and correlated with clinical and/or histological findings. The aspirates were derived from parotid gland (212 cases), submandibular gland (124 cases), and minor salivary gland (5 cases). The major diagnostic categories were unsatisfactory (10 cases), normal (100 cases), sialadenitis (74 cases), cyst (34 cases), lipoma (5 cases), pleomorphic adenoma (55 cases), Warthin's tumor (36 cases), and malignancy (27 cases). The latter included 14 primary salivary neoplasms (4 lymphomas of mucosa-associated lymphoid tissue (MALT) type, 3 adenocarcinomas, 2 squamous carcinomas, 2 adenoid cystic cacinomas, and one case each of carcinoma ex pleomorphic adenoma, undifferentiated carcinoma, and high-grade mucoepidermoid carcinoma), and 13 metastases, 9 of which were derived from squamous carcinomas of head and neck origin. Clinicopathological review showed that 88 of 91 (97%) benign epithelial tumors and 27 of 31 (87%) malignant neoplasms with adequate FNA sampling were accurately diagnosed cytologically. False-negative results were caused by sampling error (7 cases), most notably in cystic tumors, or were due to misinterpretation of uncommon neoplasms (3 cases). The overall sensitivity, specificity, and accuracy were 92%, 100%, and 98%, respectively. FNA cytology provides accurate diagnosis of most salivary gland lesions and contributes to conservative management in many patients with nonneoplastic conditions.

Adenocarcinoma↗
PubMed2000

Patients with neck lumps: can they be managed in a 'one-stop' clinic setting?

The present government has stated its intentions to expand the application of "one-stop" assessments for out-patients. To decide if this is an appropriate strategy for managing patients with neck lumps, we prospectively assessed 110 patients referred to the Neck Lump Clinic of the Otolaryngology Department of a teaching hospital. Patients were assessed clinically and with immediately reported fine needle aspiration cytology (FNAC). The accuracy of immediately reported FNAC was later compared with a final report and histology, when available. A "one-stop" visit was defined as patients who were discharged, or placed on a waiting list, after a single consultation. Eight-three (76%) patients did not have to return to the outpatient department, of which 59 (54%) were discharged. No changes occurred from immediate to final FNAC reports. If certain criteria are met, patients with neck lumps can be successfully managed in a "one-stop" setting.

Adolescent↗
PubMed2000

Powered laryngeal shavers and laryngeal papillomatosis: a preliminary report.

Carbon dioxide (CO2) laser ablation is widely accepted as the most effective first line surgical treatment of recurrent laryngeal papilloma. However, vaporization of papilloma with the CO2 laser exposes the patient and staff to a potentially infective plume. Furthermore, unsuitable pathological tissue specimens and scarring of the surrounding laryngeal architecture are inevitable consequences of the thermal energy generated by this instrument. Following their innovative use in endonasal surgery, powered laryngeal microresecting instruments (Xomed Shavers) have been developed for laryngeal surgery. We assessed the value of these new instruments in five patients who had previously undergone laser ablation. All of the patients reported that their postoperative recovery was the 'same as' or 'better than' that following laser surgery. The surgeon reported that though there was more bleeding, shaver excision of papilloma provided good clearance of disease; easy collection of pathological samples; and a potentially safer and faster alternative to laser excision.

Adult↗
PubMed1999

Is an organic/functional distinction psychologically meaningful in patients with dysphonia?

Dysphonia (hoarseness) is a common clinical condition and, if persistent, patients are referred to otolaryngology clinics for clinical examination. During the examination, a clinical distinction is often made among three types of patients: (1) those with a clear organic basis for dysphonia (cancer, vocal cord palsy): (2) those with some degree of organic pathology; and (3) those with an apparently functional etiology. Functional patients are often characterized as having a psychogenic disorder. This study assessed the psychological validity of the functional category in 204 out-patients (aged 17 to 87 years) with persistent hoarseness of types (2) and (3). Following clinical examination, a consultant otolaryngologist categorized patients as having functional or organic etiology. Subjects were then compared on measures of personality and psychological distress. Dysphonic subjects showed marked psychological distress compared with norms, and reported significantly more previous psychosomatic symptoms than norms, but there were no differences in personality or psychological distress between organic and functional subgroups of dysphonics.

Adolescent↗
PubMed1999

Pseudanthocotyloides heterocotyle (van Beneden, 1871) Euzet & Prost, 1969 (Monogenea: Polyopisthocotylea: Mazocraeidae), a parasite of herring Clupea harengus L. and sprat Sprattus sprattus L. (Teleostei: Clupeidae).

A total of 690 herring Clupea harengus L. and 88 sprat Sprattus sprattus L. caught off the west coast of Sweden, in the North Sea and off the west and south coasts of the United Kingdom, were examined for gill parasites. The monogenean Pseudanthocotyloides heterocotyle (van Beneden, 1871) Euzet & Prost, 1969 was found in 38 (5.5%) herring and one (1.1%) sprat. The parasite was significantly (P<0.05) more common off the west coast of Sweden than elsewhere and most specimens (62.5%) were found on the pseudobranchs. Only the smaller herring were infected. P. heterocotyle is redescribed and its taxonomy discussed, together with the possibility of host and parasite misidentification in previous reports.

Animals↗
PubMed1999

The genera Ceratomyxa Thélohan, 1892, Leptotheca Thélohan, 1895 and Sphaeromyxa Thélohan, 1892 (Myxosporea: Bivalvulida) in gadid fish of the northeast Atlantic.

The gall-bladders of four species of gadid fish from the North Sea and Norwegian waters were examined for myxosporeans. The host species were cod Gadus morhua L. (350 examined), haddock Melanogrammus aeglefinus (L.) (592 examined), saithe Pollachius virens (L.) (205 examined) and whiting Merlangius merlangus (L.) (368 examined). Four species of myxosporeans are redescribed from these fish. Ceratomyxa arcuata Thélohan, 1892 was the most common species and was found in whiting (41.8%) and cod (0.6%). Leptotheca informis Auerbach, 1910 was found only in whiting (6.5%). L. longipes Auerbach, 1910 was found only in haddock (6.2%). Sphaeromyxa hellandi Auerbach, 1909 was found in haddock (9.1%) and whiting (0.3%). None of the saithe examined, and no cod or haddock from Norwegian waters, was infected with these myxosporeans. All four species appear to have distributions limited to the Northeast Atlantic, with S. hellandi having a more northern distribution than the other three. The validity of reports of C. arcuata, L. informis and L. longipes from outside this area is discussed.

Animals↗
PubMed1998

Intraoperative duplex scanning for carotid endarterectomy.

OBJECTIVES: To evaluate the results of intraoperative duplex scans during carotid endarterectomy. DESIGN: Retrospective case review. MATERIALS: One-hundred consecutive intraoperative carotid duplex scans performed during carotid endarterectomy between July 1993 and December 1995 at a university teaching hospital. METHODS: Abnormalities of the B-mode image and/or the Doppler flow analysis were classified. The result of intraoperative carotid duplex scans (ICDS) were related to the events of the intraoperative course, perioperative neurologic morbidity and mortality, and to residual carotid stenosis. RESULTS: Abnormalities of the ICDS were demonstrated in 13 cases (13%). Abnormalities were classified into four types: I, internal carotid artery spasm (n = 9); II, high distal resistance flow (n = 2); III, high grade residual stenosis (n = 1); IV, intraluminal thrombosis (n = 1). Immediate intraoperative exploration and revision of the endarterectomy was performed based on the ICDS in two cases (type III and IV) and the findings of ICDS were confirmed. The other 11 cases with abnormal ICDS (types I, II) were not revised and duplex scans done 1 month postoperatively (available in 10 cases) showed normal carotid artery flow. Intraoperative angiography was performed selectively in five cases and confirmed the results of ICDS. Reversible abnormalities of the ICDS were not associated wit perioperative morbidity or residual carotid stenosis. CONCLUSIONS: Intraoperative carotid duplex scanning can be used to assess the immediate technical adequacy of carotid endarterectomy. B-mode image and Doppler flow abnormalities which are reversible can be distinguished from those which require immediate revision.

Aged↗
PubMed1998

A prospective evaluation of the feasibility of day-case microlaryngeal surgery.

An increasing number of surgical procedures are being performed on a day-case basis. In the UK otolaryngologists have been reluctant to introduce same day discharge in microlaryngeal surgery (MLS). The reason for this is the perceived risk to the airway from bleeding and oedema after MLS. The aim of this study was to investigate the feasibility of establishing a same day discharge service for MLS patients. One hundred consecutive patients under the care of one consultant otolaryngologist were recruited. A clinical street-fit assessment and objective measures of peak expiratory flow rate (PEFR) and oxygen saturation (SaO2) were recorded pre- and post-operatively. Results indicate that the PEFR and SaO2 did not change significantly during the course of the study. The street-fit criteria for discharge were satisfied in 80 per cent of patients following surgery. By combining the ASA score (American Society of Anaesthesiologists) with street-fitness 63 per cent of our patients were eligible for same day discharge.

Adult↗
PubMed1998

The tender neck: thyroiditis or thyroid abscess?

Following apparent subacute thyroiditis, a 16-year-old girl developed a left thyroid abscess thought to be secondary to steroids and haematogenous spread from a pilonidal abscess. The thyroid suppuration became recurrent and required partial thyroidectomy. Further left-sided abscess formation in the neck prompted a barium swallow which revealed the source of infection to be a sinus tract arising from the left piriform fossa. The patent fourth branchial sinus tract was later excised. All patients with a tender thyroid should have ultrasound-guided fine needle aspiration to establish the diagnosis. If suppuration is confirmed, a barium swallow is advised to exclude a sinus tract from the piriform fossa.

Abscess↗
PubMed1998

Chest computerized tomography scanning in patients presenting with head and neck cancer.

Between 1 to 16% of patients with head and neck squamous cell carcinoma (HNSCC) have synchronous tumours; the majority (> 50%) occurring within the lung. Previous studies have relied upon endoscopy and chest radiographs. The aim of this study was to determine the incidence of synchronous intrapulmonary tumours in this group of patients using computerized tomography (CT) scanning. Over 36 months, 111 consecutive patients were assessed at presentation by contrast enhanced CT scanning from the skull base to the diaphragm. Chest scans showed intrapulmonary lesions in 17 patients and 10 have, with time, been confirmed as neoplastic. These allowed treatment of three primary bronchial carcinomas following radical treatment of the index tumour and cancellation of radical treatment in five patients with metastases. Two patients with possible metastases at presentation underwent radical treatment to the index tumour with subsequent follow-up confirming metastatic chest disease. All 10 patients eventually died of either locoregional or metastatic disease. This is one of the first prospective reports of chest scanning in patients with head and neck cancer. An additional chest scan in this group, many of whom undergo a staging scan of the neck, requires an extra 10 min with no further contrast and in this study yielded a synchronous tumour rate of 9%.

Carcinoma, Squamous Cell↗
PubMed1997

Paediatric neck masses--a diagnostic dilemma.

Three hundred and sixty children who had a head and neck mass excised during 1987 to 1992 at the Royal Hospital for Sick Children, Glasgow were studied. There were 210 males and 150 females with a mean age of 60.7 months (0.5 to 198 months). Pilomatrixomata/sebaceous cysts (34 per cent), thyroglossal cysts (13 per cent), branchial remnants (nine per cent) and dermoids (nine per cent) accounted for almost two-thirds of the 264 non-lymphadenomatous benign lesions excised. Ninety-three lymphadenopathy masses consisted of 60 with reactive hyperplasia, 21 with Mycobacterium infection and 12 lymphomas. There were three solid malignant tumours, two were rhabdomyosarcomata and one disseminated round cell tumour. The correlation between clinical diagnosis and histopathology of benign non-lymph node masses and solid tumours was 90 per cent and 100 per cent respectively, in benign lymph nodes, 66 per cent, but was poor in differentiating lymph node content. The mean time from presentation of a swelling to its excision was almost a year and the mean in-patient stay for excision of a mass was almost five days. The role of fine needle aspiration cytology (FNAC) in arriving at a diagnosis and reducing patient morbidity is discussed.

Adolescent↗
PubMed1997

Myeloproliferative disease and myelodysplastic syndrome induced by transplantation of bone marrow cells expressing mutant p53.

p53 mutations are the most common genetic alterations observed in human cancers including lymphomas and leukemias. We have previously shown that transduction of normal murine hematopoietic cells with mutant p53 alone in vitro results in an enhanced proliferative capacity and modified differentiation potential of transduced cells. In order to investigate further the role of mutant p53 in hematopoietic cell transformation, mutant p53-transduced bone marrow cells were used to reconstitute the hematopoietic system of lethally irradiated mice. The results show that overexpression of mutant p53 can initiate the transformation of immature murine hematopoietic cells in vivo and induce two types of hematopoietic disorders, myeloproliferative disease and myelodysplastic syndrome.

Animals↗
PubMed1997

Voice therapy for dysphonia--still more art than science?

Before evaluation of the efficacy of voice therapy is possible it is necessary to define established practice. The aim of this study therefore was to assess the prevailing treatment strategies among UK voice therapists for commonly presenting causes of dysphonia.

Humans↗
PubMed1996

The use of the CO2 laser for airway maintenance in obstructive supraglottic carcinoma.

CO2 laser 'debulking' of obstructive supraglottic tumours is an alternative to tracheostomy to restore the compromised airway. Two patients have successfully undergone radiation therapy after laser vaporization of their large supraglottic tumours, and did not require tracheostomy. This technique is relatively simple, avoids the morbidity of tracheostomy and facilitates early irradiation.

Aged↗