Transoral laser surgery for laryngeal carcinoma: has Steiner achieved a genuine paradigm shift in oncological surgery?

Transoral laser microsurgery applies to the piecemeal removal of malignant tumours of the upper aerodigestive tract using the CO2 laser under the operating microscope. This method of surgery is being increasingly popularised as a single modality treatment of choice in early laryngeal cancers (T1 and T2) and occasionally in the more advanced forms of the disease (T3 and T4), predominantly within the supraglottis. Thomas Kuhn, the American physicist turned philosopher and historian of science, coined the phrase 'paradigm shift' in his groundbreaking book The Structure of Scientific Revolutions. He argued that the arrival of the new and often incompatible idea forms the core of a new paradigm, the birth of an entirely new way of thinking. This article discusses whether Steiner and colleagues truly brought about a paradigm shift in oncological surgery. By rejecting the principle of en block resection and by replacing it with the belief that not only is it oncologically safe to cut through the substance of the tumour but in doing so one can actually achieve better results, Steiner was able to truly revolutionise the management of laryngeal cancer. Even though within this article the repercussions of his insight are limited to the upper aerodigestive tract oncological surgery, his willingness to question other peoples' dogma makes his contribution truly a genuine paradigm shift.

Presentation of laryngeal papilloma in childhood: the Leeds experience

INTRODUCTION

The human papilloma virus (HPV) can cause laryngeal papillomatosis in childhood. The aetiology is thought to be vertical transmission. Clinically these children are usually asymptomatic for the first 6 months of life. As the papillomas develop locally, symptoms begin to develop. The symptoms range from voice change to frank hoarseness, and 'noisy' breathing, most commonly inspiratory stridor.

METHOD

Clinical images from microlaryngoscopy and bronchoscopy over a 12-year period were assessed for laryngeal papilloma.

RESULTS

In Leeds seven cases presented to the specialist centre over the past 12 years, the average age at presentation was 6.8 years and duration of onset of symptoms to specialist review was 21 months. Five of the children had been treated for asthma and two presented in extremis.

CONCLUSION

The take home message for clinicians is hoarse voice associated with shortness of breath needs specialist referral.

A discussion of airway and respiratory complications along with general considerations in obese patients

Obesity is defined as the degree of excess weight associated with adverse health consequences. Within Great Britain, it is reported that a quarter of men and women are obese; these rates have trebled over the past 20 years. In 2001, it was estimated that obesity cost the National Health Service at least half a billion pounds, with a further two billion pounds lost on lower productivity and lost output. Obesity poses a significant risk factor for diseases, such as coronary heart disease, diabetes mellitus and certain forms of cancer, amongst others. Obese individuals pose significant problems to the clinician because of airway and respiratory complications. Sleep apnoea, obesity-hypoventilation syndrome, pulmonary atelectasis are associated with obesity and tracheostomy insertion is made all the more difficult in these patients. This article aims to discuss some of these issues relevant to the clinician and examine present strategies for dealing with them.

High-temperature thermal destruction of poultry derived wastes for energy recovery in Australia

The high-temperature thermal destruction of poultry derived wastes (e.g., manure and bedding) for energy recovery is viable in Australia when considering resource availability and equivalent commercial-scale experience in the UK. In this work, we identified and examined the opportunities and risks associated with common thermal destruction techniques, including: volume of waste, costs, technological risks and environmental impacts. Typical poultry waste streams were characterised based on compositional analysis, thermodynamic equilibrium modelling and non-isothermal thermogravimetric analysis coupled with mass spectrometry (TG-MS). Poultry waste is highly variable but otherwise comparable with other biomass fuels. The major technical and operating challenges are associated with this variability in terms of: moisture content, presence of inorganic species and type of litter. This variability is subject to a range of parameters including: type and age of bird, and geographical and seasonal inconsistencies. There are environmental and health considerations associated with combustion and gasification due to the formation of: NO(X), SO(X), H(2)S and HCl gas. Mitigation of these emissions is achievable through correct plant design and operation, however, with significant economic penalty. Based on our analysis and literature data, we present cost estimates for generic poultry-waste-fired power plants with throughputs of 2 and 8 tonnes/h.

Towards the large-scale synthesis of carbon nanotubes in fluidised beds

Carbon nanotubes (CNTs) are a form of crystalline carbon with extraordinary properties, making them valuable in a broad range of applications. However, the lack of suitable large-scale manufacturing techniques, which we define as being of the order 10000 tonnes per annum, continues to inhibit their widespread use. Of the three established synthesis methods for CNTs: (i) chemical vapour deposition (CVD), (ii) laser ablation, and (iii) arc discharge, CVD techniques show the greatest promise for economically viable, large-scale synthesis. In particular, the fluidised bed CVD (FBCVD) technique, where the CVD reaction occurs within a fluidised bed of catalyst particles, has the potential to produce high quality CNTs, inexpensively, in large quantities. In this work we report on the development of a catalytic chemical vapour deposition process, using batch fluidised bed reactors, for the synthesis of straight and spiral carbon nanotubes at pilot scale (up to 1 kg/hr). We believe this to be the first report of the synthesis of spiral carbon nanotubes using fluidised bed CCVD. Iron, nickel and cobalt transition metal catalysts supported on non-porous alumina substrates were fluidised in a mixture of nitrogen, hydrogen and ethylene at temperatures between 550 and 800 degrees C for between 15 and 90 minutes. Nanotube yield was inferred from thermogravimetric analysis and the quality and size of the CNTs from transmission electron microscopy. Conflicting information in the literature about the influence of synthesis parameters on CNT properties suggests that further investigation is necessary to understand the synthesis process at a fundamental level, i.e., independent of reactor design and operation.

A program of acquired immune deficiency syndrome education for nurses in Romania

After the fall of the communist government in Romania, many children were found to be human immunodeficiency virus (HIV) infected. The majority of these children were abandoned and currently live in orphanages. The children have been cared for on a day-to-day basis by nurses with little general nursing education and even less HIV education. The Romanian-American Pediatric AIDS Education and Clinical Research Program was established at Texas Children's Hospital and Baylor College of Medicine in May, 1996 to aid in the education of Romanian nurses. Syllabi developed by the U.S. nursing team were initially piloted in three pediatric HIV centers in Romania in July, 1997. Since that time, two annual nursing symposia have been held offering topics on general pediatrics and HIV-related content. The purpose of this article is to describe a program of HIV education for nurses in Romania.

A pilot study of combination therapy with indinavir, stavudine (d4T), and didanosine (ddI) in children infected with the human immunodeficiency virus

Twelve children infected with the human immunodeficiency virus were treated orally with indinavir, stavudine, plus didanosine for 12 to 48 weeks. Therapy was limited in some cases by nonadherence, intolerance, toxicity, and virologic failure. Marked increases in CD4+ lymphocyte counts and decreases in plasma human immunodeficiency virus RNA concentrations suggest that the regimen has potent antiviral activity.

Combination therapy with stavudine and didanosine in children with advanced human immunodeficiency virus infection: pharmacokinetic properties, safety, and immunologic and virologic effects

OBJECTIVES

To obtain preliminary information on the pharmacokinetic properties, tolerance, safety, and antiviral activity of combination therapy with stavudine and didanosine in children with advanced human immunodeficiency virus (HIV) infection.

METHODS

Eight children (median age, 6.6 years; range, 2.8 to 12 years) with advanced HIV disease (median CD4 + lymphocyte count at baseline, 42 cells/ microL; range, 8 to 553 cells/microL) were treated with stavudine (2 mg/kg per day in two divided doses) and didanosine (180 mg/m2 per day in two divided doses) for 24 weeks. Seven children had histories of prior zidovudine therapy. All children had received stavudine alone for 19 to 33 months before the addition of didanosine to the treatment regimen. Children were assessed clinically and with laboratory studies at baseline, weekly through week 4 of combination therapy, and every 4 weeks thereafter.

RESULTS

Analysis of stavudine and didanosine plasma half-life values, clearances, and area under the plasma concentration-versus-time curves revealed no obvious clinical pharmacokinetic interaction between the drugs through study week 12. Combination therapy was well tolerated, and there were no drug-associated clinical or laboratory adverse events. Signs and symptoms of peripheral neuropathy were not observed. All three children with baseline CD4 + lymphocyte counts greater than 50 cells/muL had greater than 20% increases in their counts within the first 12 weeks of therapy; CD4 + lymphocyte count increases were not observed in the other children. Plasma HIV RNA concentrations showed median declines of 0.88 log10 (range, -3.41 log10 to 0.31 log10) and 0.30 log10 (range, -0.63 log10 to 0.89 log10) at study weeks 12 and 24, respectively.

CONCLUSIONS

Combination therapy with stavudine and didanosine was well tolerated and safe in this small group of children with advanced HIV disease. Plasma HIV RNA concentration declines suggest a favorable effect of therapy on virus load. These findings should be confirmed, and the regimen's clinical efficacy should be examined, in controlled studies of HIV-infected children with less-advanced disease.

A phase I/II evaluation of stavudine (d4T) in children with human immunodeficiency virus infection

OBJECTIVES

To determine the pharmacokinetic properties, tolerance, safety, and preliminary activity of stavudine in human immunodeficiency virus (HIV)-infected children.

DESIGN

Phase I/II, open and dose-ranging (0.125 to 4 mg/kg/day in two divided doses).

PATIENTS

Thirty-seven HIV-infected children (median age, 5.5 years; range, 7 months to 15 years) with a median CD4+ lymphocyte count at baseline of 242 cells/microL (range 2 to 2290 cells/microL). Thirty children had symptomatic HIV disease at entry; seven had HIV-related immunosuppression alone. Twenty-nine subjects had a history of prior zidovudine (ZDV) therapy.

RESULTS

As compared with adults receiving the same weight-adjusted doses, the children we studied had lower maximum observed stavudine plasma concentrations (CMAX) and area under the plasma concentration versus time curves (AUC), and more rapid stavudine elimination. The absolute oral bioavailability of the drug ranged from 61% to 78%. There was no plasma accumulation of the drug between day 1 and week 12. Week 12 cerebrospinal fluid stavudine concentrations in seven subjects, obtained approximately 2 to 3 hours after oral doses, ranged from 16% to 97% of concomitant plasma concentrations. Stavudine was well-tolerated and there were no dose-related clinical or laboratory adverse events. One subject with baseline neurologic abnormalities experienced a transient episode of apparent pain or discomfort in her fingers, possibly related to stavudine. All other adverse events were attributed to underlying disease. Stavudine activity, measured indirectly by CD4+ lymphocyte count and serum p24 antigen concentration changes, was observed in some subjects. Progression of HIV disease and survival correlated with prior ZDV therapy, HIV disease classification, baseline CD4+ lymphocyte count, and weight growth velocity.

CONCLUSIONS

Stavudine appears to hold promise for the treatment of HIV infection in children. Its pharmacokinetic properties are consistent and predictable, and it appears to be remarkably well-tolerated and safe. Although our study was not designed to assess the drug's efficacy, preliminary clinical and laboratory evidence of activity was observed.

Clinical outcomes of total laryngectomy for laryngeal carcinoma

Background: Controversy exists as to the management of advanced laryngeal carcinoma. In general primary radical surgery is favoured. Objective: The aim of this study was to analyse the clinical outcome of patients having total laryngectomy for cancer of larynx. Materials and methods: This study was a retrospective case note review and questionnaires were used for evaluating voice handicap. These laryngectomies included in this study were performed by the senior author (CJW) from January 2001 till June 2007 at Leeds General Infirmary, Leeds. Some of the patients had partial or total pharyngectomy in addition to total laryngectomy. Results: In this study a total of 59 patients were included. Seventeen (28.8%) of these patients had preoperative radiotherapy and laryngectomy was performed for residual or recurrent disease. The initial TNM staging of the tumour ranged from T1N0 to T4N2C. Tracheoesophageal puncture for speech prosthesis was done in 48/59 (81.4%) patients. Post-operative complications were seen in 30.5% (18/59) patients. In this study group 9 patients (15.2%) developed pharyngocutaneous fistulas. For communication 31/51 (60.8%) patients were using speech valves. In this study 30.4% had minimal, 26.1% moderate and the rest 43.4% feeling severely handicapped with regards to voice use after total laryngectomy. Five year survival after laryngectomy in this study was 65.2%. Conclusion: Long term disease control and survival is achievable with total laryngectomy with or without postoperative radiotherapy with minimal risks in patients with advanced carcinoma of larynx. Key words: Laryngectomy; Larynx; Carcinoma DOI: 10.3126/kumj.v7i3.2734 Kathmandu University Medical Journal (2009) Vol.7, No.3 Issue 27, 258-262