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Biomedical subjects

D J Howard

Publications and source records attributed to D J Howard.

At least 19 recordsLinked to original sources
PubMed2006

Are the demographics for squamous cell cancer in the head and neck changing in the United Kingdom?

Head and neck squamous cell carcinoma is well known to be more common in men than women. Smoking and alcohol are the key risk factors causing such malignancies and there are several publications which have suggested that the prevalence of these diseases is increasing more in women than in men in western countries due to increased smoking and alcohol use. We collected our data at the Institute of Laryngology and Otology from the last 45 years and analysed the disease ratios in male to female patients in different sites within the head and neck. Our results revealed a decreasing male to female ratio, though this was not statistically significant. However, it draws attention to the increasing number of women with head and neck cancer, which may reflect their increasing use of cigarettes and alcohol.

Aged↗
PubMed2006

Objective sizing of upper airway stenosis: a quantitative endoscopic approach.

OBJECTIVE: In patients with airway stenosis, anatomy of the lesion determines the magnitude of the biomechanical ventilatory disturbance and thus the nature and severity of symptoms. It also gives information about biology, likelihood of response to treatment, and prognosis of laryngotracheal lesions. Accurate airway sizing throughout treatment is therefore central to managing this condition. We developed a method for objective assessment of airway lesions during endoscopy. METHODS: We used airway simulations to investigate the effects of endoscope tilt and lens distortions on measurement accuracy, devising and validating clinical rules for quantitative airway endoscopy. A calibrator was designed to assess lesion length, location, and cross-section during tracheoscopy. RESULTS: It proved possible to calculate the length and location of the stenosis using simple mathematics. Cross-section measurements were more than 95% accurate, independent of endoscope tilt and without making assumptions about endoscope optics and visuospatial distortion, for both pediatric and adult airway dimensions. The technique was used to characterize airway lesions in 10 adult patients with an average age of 48 years undergoing therapeutic laryngotracheoscopy. Lesions occurred on average 36 mm below the glottis (range, 21-54 mm) and were 9.3 mm long (5-17 mm). The average pretreatment airway cross-section was 48.3 mm, increasing to 141.1 mm after laser therapy. Two independent observers calculated airway cross-sections, achieving an interobserver concordance of 0.98. CONCLUSIONS: This method can be used to objectively and precisely determine the anatomy of airway lesions, allowing accurate documentation of lesion characteristics and surgical results, serial monitoring throughout treatment, and comparison of outcomes between different centers.

Adult↗
PubMed2005

How we do it: transnasal fibreoptic oesophagoscopy.

KEYPOINTS: Transnasal fibreoptic oesophagoscopy (TFO) allows the upper aerodigestive tract, from the nasal vestibule to the gastric cardia to be examined in the outpatients department without sedation. This permits patients with symptoms of upper aerodigestive pathology to be investigated at the initial consultation without the need for inpatient endoscopy or swallow studies. The technique is easily learned, and is statistically comparable with standard flexible nasoendoscopy in respect of procedural pain and discomfort. It is highly cost-efficient, paying for itself within 1 year, and thereafter leading to cost savings of over 80%. Its role can be expanded to encompass investigating patients with potentially malignant disease processes, as well as outpatients "panendoscopy" and biopsy, and a number of therapeutic interventions.

Ambulatory Care↗
PubMed2003

Quality of life of patients undergoing surgical treatment of head and neck malignancy.

This study prospectively follows changes in quality of life (QoL) of 40 patients undergoing surgical treatment for head and neck malignancy over a 1-year period, using the University of Washington QoL questionnaire version 4.0. The tumour types included oral, oropharyngeal, hypopharyngeal, oesophageal, laryngeal, sinonasal and thyroid carcinomas. Mean overall QoL scores were significantly worse at 3 and 6 months (P < 0.05) and returned to around preoperative scores at 12 months (P = 0.11). Oropharyngeal, laryngeal, sinonasal and thyroid subsites all maintained QoL scores at each time point. QoL scores for hypopharyngeal and oral subsites dropped markedly at 3 and 6 months but returned to around preoperative levels at 12 months. The domains most affected by treatment varied depending on tumour subsite. For the population as a whole, their appearance, activity, speech, shoulder and saliva domains were all significantly less at 12 months. Anxiety scores were significantly better at 12 months.

Aged↗
PubMed2003

Management of thyroglossal tract disease after failed Sistrunk's procedure.

Sistrunk's procedure for thyroglossal duct remnants has a very high success rate, there remains the occasional patient, however, that will have recurrent disease despite a competently performed operation. Applied anatomy and embryology proffer a solution to this problem. Extending the Sistrunk operation, with an anterior wide local excision remaining within normal tissue, enables removal of the entire thyroglossal tract remnant. A retrospective case note review was conducted to study our experience using this extended procedure to treat patients with thyroglossal tract disease that had recurred after a previous Sistrunk's operation. Six patients aged from five to 33 years were included in the study. There was one recurrence and the complication rate was comparable to the standard operation. It was concluded that a wide local excision is a valuable extension of the Sistrunk operation for the management of recurrent disease.

Adult↗
PubMed2001

Reproductive processes in two oak (Quercus) contact zones with different levels of hybridization.

Patterns of reproductive isolation between two sympatric species of oaks, Quercus gambelii and Q. grisea, that exhibit strong ecological differentiation were examined. A full diallel cross using four trees of each species (i.e. all possible pollinations among eight trees) was performed. This design was repeated at two sites that represent different outcomes of sympatry: (1) a xeric mountain ridge where many hybrids are established (HZ); and (2) a mesic valley bottom where virtually no hybrids are established (MOCYN). By measuring fruit survival at several developmental stages, both the timing and strength of reproductive barriers within and between sites, species, cross types, and pollen dosage levels were examined. In three of four cases, heterospecific fruit set was significantly reduced compared to conspecific fruit set. This reduction occurred after the time of fertilization, but before the onset of embryo growth. Increasing the dose of pollen from an average of 9-194 grains/stigma did not affect this result. Thus, early postfertilization processes play a strong role in species fidelity in these oaks. Quercus gambelii experienced a five-fold decrease in conspecific fruit set at HZ relative to MOCYN. In contrast, heterospecific fruit set of Q. gambelii was the same at both sites. Poor Q. gambelii pollen performance is implicated as playing the major role in this result. One Q. gambelii individual at HZ was highly fecund, and had higher heterospecific than conspecific fruit set; slight introgression in this tree was detected uisng RAPD markers. The Environmental Emasculation Hypothesis that posits that environmental stress can increase the probability of hybrid formation by reducing the competitive ability of male gametes of one species is proposed.

Crosses, Genetic↗
PubMed2001

Spatio-temporal dynamics of the Allonemobius fasciatus- A. socius mosaic hybrid zone: a 14-year perspective.

Long-term studies of hybrid zones can provide valuable insight into a number of questions that have long attracted the attention of evolutionists. These questions range from the stability and fate of hybrid zones to the relative fitness of hybrids. In this paper we report the results of a 14-year survey of the Allonemobius fasciatus-Allonemobius socius hybrid zone. Populations were collected intensively in 1986 and 1987 and then more sporadically through the end of the 1980s and throughout the 1990s. By documenting changes in the genetic composition of populations near and within the zone during this period of time we assessed: the strength of the reproductive isolation between the two species; the relative growth rates (which can be considered a surrogate of relative fitness) of genotype classes corresponding to hybrids and to pure species individuals; and, the power of single-year and multi-year measurements of relative growth rates to predict changes in the genetic composition of mixed populations through time. In brief, we found very large year-to-year variation in the relative growth rates of pure species and hybrid individuals. This variation may reflect the fact that both species are at the edge of their range and perhaps at the limits of their ability to deal with environmental perturbations. As a consequence of the variation, even multi-year estimates of relative growth rates often provided imprecise predictions regarding the future genotypic composition of mixed populations. Despite our limited ability to predict the dynamics of individual populations, some trends are apparent. A. socius, the southern species, has clearly increased in frequency along a transect through the Appalachian Mountains, indicating that the zone is moving north in this region. In contrast, the zone appeared to be more stable along the East Coast transect. Within mixed populations, character-index profiles are often bimodal and stable through time, indicating relatively strong reproductive isolation between the two species that is not being reinforced, nor is it breaking down.

Alleles↗
PubMed2001

Recurrence and its avoidance in juvenile angiofibroma.

OBJECTIVE: Angiofibroma is a highly vascular lesion for which a wide range of surgical approaches has been recommended. Irrespective of the approach, a significant and often rapid recurrence rate is reported in all major series. AIM: To consider the impact of lessons learned from imaging on the recurrence rate of angiofibroma. MATERIAL AND METHODS: From a cohort of 90 male patients with histologically proven angiofibroma, 40 individuals were studied. The recurrence rate in 20 cases treated before March 1998 was compared with that in 19 cases treated thereafter. In the latter group, an additional exploration of the basisphenoid had been undertaken. RESULTS: The two cohorts were comparable in age range (7-27 y and 11-24 years, respectively), and all had been treated by midfacial degloving. In the first group, 8 recurrences occurred which were multiple in 1 patient. In the next 19 patients, the area of the pterygoid canal was meticulously explored and the basisphenoid drilled to remove all residual tumor. No recurrences have occurred in this group during a follow-up of between 6 months to 3 years. CONCLUSION: Meticulous removal of angiofibroma infiltrating the pterygoid canal and basisphenoid is paramount to avoid "recurrence."

Adolescent↗
PubMed2000

Laryngeal chondrosarcoma: a 24-year experience at the Royal National Throat, Nose and Ear Hospital.

This paper presents a review of the experience of 12 patients with chondrosarcoma of the larynx treated at The Royal National Throat, Nose and Ear Hospital, London, over the last 24 years. This represents the largest European series and the third largest in the world. Chondrosarcoma is the most frequent non-epithelial malignant tumor of the larynx, with 83.3% of cases arising from the cricoid cartilage in our series. We have shown that deep wedge biopsy with a CO2 laser, aided by computerized tomography scanning, gives the most reliable diagnosis. Laryngeal chondrosarcoma is characterized by indolent growth, a potential for local recurrence and, infrequently, by metastases. The treatment details of our patients are discussed. Adequate partial resection is often successful and use of CO2 laser as the initial treatment in five of these cases is presented.

Adult↗
PubMed2000

The role of partial laryngeal resection in current management of laryngeal cancer: a collective review.

A spectrum of treatment plans and surgical procedures is available for management of early and moderately advanced laryngeal cancer. While the approach of chemotherapy and irradiation, or irradiation alone, followed by total laryngectomy for failure is often employed in practice by present day clinicians, the options of conventional conservation surgery (CCS), transoral endoscopic laser surgery (TLS) and supracricoid partial laryngectomy (SCPL) provide a wide choice of treatments that may help attain the goal of cure with preservation of laryngeal function and integrity of the airway. While CCS has been supplanted for many early-stage lesions by TLS and for more advanced stages by SCPL, centres throughout the world have reported favourable results with CCS, which is often modified to include resection of more extensive tumours than was previously possible. During the past decade a number of extended CCS procedures have been developed for management of glottic tumours involving both vocal cords and the anterior commissure, the paraglottic space and with vocal cord fixation, and for supraglottic tumours involving the glottis or hypopharynx. TLS has proved an effective, minimally invasive and functionally satisfactory procedure for management of suitable T1 and T2 glottic cancers, and stage I-III supraglottic cancers. The procedure may be effectively employed in combination with neck dissection and postoperative radiotherapy when necessary, particularly for moderately advanced supraglottic carcinomas. SCPL has proven effective in management of glottic and supraglottic cancers of all stages, even with involvement of paraglottic space and thyroid cartilage, provided at least one arytenoid unit can be preserved with clear margins. Invasion of cricoid cartilage is the most significant limitation for this procedure. All three surgical approaches have been employed for irradiation failure, but with greatly increased failure and complication rates compared with the results of treatment of non-irradiated patients. Thus a decision to treat laryngeal cancer initially with irradiation may preclude a satisfactory result from partial laryngectomy should radiation fail. The treatment of laryngeal cancer should be individualized according to the size and extent of the tumour, the age and physical condition of the patient, and the skill and experience of the surgeon with various treatment modalities and surgical procedures.

Combined Modality Therapy↗
PubMed1999

A third decade's experience with the gastric pull-up operation for hypopharyngeal carcinoma: changing patterns of use.

Gastric transposition has been used extensively in this department since 1965 for reconstruction following pharyngolaryngoesophagectomy (PLO). A previous report by Harrison and Thompson in 1986 detailed our experience with 101 cases dating back to 1965. Here we review our experience between 1986-1996. Medical records of 41 cases were examined. The primary site and stage of tumour and associated lymph nodes, patient demographics, complications, in-patient mortality and survival as demonstrated by the Kaplan-Meier method were recorded. Gastric transposition is now used for more extensive tumours: 70 per cent T4 (83 per cent pathologically T4) compared to 21 per cent in the previous report. A high proportion of 'radiation failures' remains (54 per cent). The in-hospital mortality has fallen from 11 per cent to seven per cent. The five-year-survival calculated using the Kaplan-Meier method is 11 per cent. This procedure is increasingly being used as a palliative procedure aiming to restore swallowing in the relatively young patient who has very extensive hypopharyngeal carcinoma. Long-term survival rates specific to this operation have fallen. This is attributed to patient selection for the procedure with the vast majority having disease extending into bone, cartilage or soft tissues (T4). The defect created by the resection of less extensive tumours are now increasingly reconstructed with jejunal free flaps and musculocutaneous flaps.

Adult↗
PubMed1999

The role of midfacial degloving in modern rhinological practice.

The midfacial degloving approach has been available for twenty five years and is slowly increasing in popularity in the management of extensive benign lesions of the sinonasal region, for selected malignancy in this area and to afford access to the nasopharynx and infra-temporal fossa. The advantages, applications and low complication rate are presented in a cohort of 86 patients, ranging from three to 79 years of age with a mean follow-up of 5.5 years. Seventy-seven per cent of the group had benign pathology of which juvenile angiofibroma was the commonest (40 cases). The 20 cases of malignant disease were a heterogeneous group histopathologically including adenoid cystic carcinoma (four cases), malignant schwannoma (two cases), rhabdomyosarcoma (two cases) and squamous cell carcinoma (two cases). Five underwent bilateral radical maxillectomies combined with orbital clearance in one patient. Complications include oro-antral fistula (three cases) and epiphora (three cases) all of which were successfully treated.

Adenoids↗
PubMed1999

Management options and survival in malignant melanoma of the sinonasal mucosa.

OBJECTIVES/METHODS: To determine whether surgery combined with radiotherapy confers any survival benefit on radical local excision alone in the management of mucosal malignant melanoma of the nose and sinuses. STUDY DESIGN: Retrospective review. METHODS: From a cohort of 72 patients treated between 1963 and 1996 within a single unit, complete data were available for 58 individuals who were examined to determine whether there was any significant statistical difference in local control and/or survival between those receiving surgery and those receiving combined surgery and radiotherapy. RESULTS: There were 30 men and 28 women. Their ages ranged from 39 to 90 years (mean, 64 y). Twenty-nine patients underwent surgery alone; 23 patients underwent surgery and radiotherapy; 6 patients received surgery and chemotherapy; and 3 patients received surgery, chemotherapy, and radiotherapy. Primary surgery included lateral rhinotomy (42 cases), maxillectomy (8 cases [orbital clearance in 3 cases]), craniofacial resection (3 cases), total rhinectomy (3 cases), and endoscopic clearance (2 cases). Survival ranged from 1 to 228 months with rapid patient loss due to local (and/or systemic) disease during the first 36 months, irrespective of the treatment modality. Overall 5-year actuarial survival was 28%, and overall 10-year actuarial survival 20%, with a median survival of 21 months. There was no statistical difference in local control or survival between patients receiving surgery alone and those receiving surgery and radiotherapy, irrespective of whether this treatment was given in the early part of the series (i.e., before 1983) or thereafter. The addition of chemotherapy had no impact on survival, nor did the site of the tumor, the surgical procedure, the presence of lymph node metastases or the age of the patient. CONCLUSION: In this large cohort of sinonasal melanoma, overall survival was poor and did not appear to be improved by the addition of radiotherapy.

Adult↗
PubMed1999

Synovial chondromatosis in raptors.

Fourteen raptors, consisting of 13 great horned owls (Bubo virginianus) and one red-tailed hawk (Buteo jamaicensis), from central and north central Minnesota, western Wisconsin, and eastern South Dakota (USA) were admitted to a raptor rehabilitation center between June 1992 and June 1995, with perisynovial and synovial chondromatosis affecting multiple joints. Birds were severely debilitated primarily due to loss of shoulder motion. The etiology of these lesions in raptors is unknown.

Animals↗
PubMed1998

Oxidative DNA damage in mouse heart, liver, and lung tissue due to acute side-stream tobacco smoke exposure.

Environmental tobacco smoke (ETS) is a hotly debated social, political, and scientific issue, pitting smokers' rights against the health and safety of nonsmokers. Striking an acceptable balance between the two depends largely on the potential health hazard assessment of ETS. Studies from this laboratory have shown that exposure to side-stream cigarette smoke (SSS), the major component of ETS, significantly increases oxidative stress in mouse heart, liver, and lung tissues. This study measures the level of oxidative damage to mouse liver, lung, and heart DNA as a result of this oxidative stress. Adult female Balb/c mice were exposed to a regimen consisting of sequences of a 30-min exposure followed by a 90-min nonexposure. This regimen was performed once for the single exposure and repeated three times for the triple exposure. The heart, lung, and liver were excised from the mice, and DNA was extracted and analyzed for the presence of the oxidative product 8-hydroxy-2'-deoxyguanosine (8-OHdG). In all three tissues, the exposure increased the presence of 8-OHdG above the control levels. In some instances, the increased levels returned to normal by the end of the nonexposure period, while other tissues showed a further increase following nonexposure. These studies demonstrate that limited exposure to SSS produces measurable DNA oxidative damage.

8-Hydroxy-2'-Deoxyguanosine↗