Relationships between environmental changes, maturity, growth rate and plasma insulin-like growth factor-I (IGF-I) in female rainbow trout.

Size reflecting growth rate, energy balance or nutritional status is regarded as an important determinant of the ability of trout to undergo puberty. The relationship of a change in photoperiod, either natural (SNP) or advancing (ADV), with growth, IGF-I and reproduction was investigated in virgin female rainbow trout. Under SNP 63% of the population attained maturity while only 29% spawned 6 months in advance in the ADV regime. Under SNP both size and growth rate in late spring-early summer appeared to determine whether an individual may initiate reproduction while condition factor appeared to be a better predictor in the ADV regime. A complete seasonal relationship between plasma IGF-I, daylength and temperature was demonstrated under natural conditions, and provides direct evidence for the relationship between reproduction and IGF-I. Conversely, trout maintained under ADV exhibited a significantly different plasma IGF-I profile relative to those under a natural photoperiod. Furthermore, IGF-I levels accurately reflected growth rate prior to elevations in sex steroids, suggesting that IGF-I may provide an endocrine signal between the somatotropic and reproductive axes that growth rate and/or size is sufficient to initiate gonad development. In addition, maturing individuals under SNP typically expressed higher circulating IGF-I levels than those that remained immature and may reflect a greater opportunity for IGF-I to act on the pituitary to stimulate gonadotropin production. We observed elevated levels in maturing fish for 3 months under SNP compared to only 1 month under ADV were observed. This may reflect a reduction in the window of opportunity to initiate reproduction under advancing photoperiods and hence explain the reduction in fish successfully recruited.

Photoperiod influences growth rate and plasma insulin-like growth factor-I levels in juvenile rainbow trout, Oncorhynchus mykiss.

The effect of different photoperiod regimes and the subsequent influence of melatonin on growth and insulin-like growth factor-I (IGF-I) were assessed in juvenile rainbow trout. In Experiment 1, triplicate groups of all female underyearling rainbow trout were exposed to one of three photoperiods; simulated natural photoperiod (SNP), constant short-days (LD 8:16), or constant long-days (LD 18:6) from June to December 2000 under ambient water temperatures. Fish exposed to LD 18:6 grew to a significantly heavier mean weight than the other treatments. Regression analysis showed a strong correlation between circulating plasma IGF-I, growth rate and temperature. Furthermore, it was apparent that fish exposed to LD 18:6 expressed significantly higher circulating levels of IGF-I. In a second experiment, duplicate groups of all female yearling trout were exposed to one of three photoperiods; SNP, LD 8:16, or constant light (LL), with sub groups receiving either a slow-release melatonin implant (18 mg), sham implant or left intact (control). LL increased growth rate in controls, reaching a significantly greater weight than SNP or LD 8:16 photoperiods but did not affect circulating IGF-I levels. Melatonin implants reduced growth rate in all photoperiod treatments below that of their respective controls but again did not affect circulating IGF-I levels. No differences in growth rate were found in implanted fish between photoperiods suggesting that a diel cycle of melatonin is necessary for the perception of daylength. These results would indicate that extended photoperiods (LD 18:6) may cause direct photostimulation of growth through up-regulation of IGF-I production. In contrast, in the absence of a changing diel melatonin signal, growth appeared to be maintained by a possible underlying endogenous rhythm, which was phase advanced under LL, as such plasma IGF-I levels simply reflected growth rate rather than photostimulation of the somatotropic axis. Overall, these findings indicate that measuring plasma IGF-I may be a useful tool for studying environmental influences on growth in rainbow trout.

An audit of pharyngeal pouch surgery using endoscopic stapling. The patient's viewpoint.

We report an audit designed to assess patient satisfaction resulting from pharyngeal pouch surgery using an endoscopic stapler. A personal series of 16 patients all operated on by the senior author over a 3-year period is reported. Information was gathered using a retrospective telephone questionnaire to establish pre- and postoperative symptoms, complications of surgery and patient satisfaction. This showed endoscopic pharyngeal pouch surgery to be successful in the majority of cases. Eighty-seven percent of patients felt better as a result of surgery. Seventy-five percent had no symptoms postoperatively. This series shows that surgery on pharyngeal pouches results in significant improvement in patient symptoms with minimal morbidity and mortality.

Polyamino acids as catalysts in asymmetric synthesis.

The use of polyamino acids in asymmetric organic synthesis is reviewed. Particular emphasis is placed on the asymmetric epoxidation of alpha,beta-unsaturated ketones with hydrogen peroxide in the presence of polyalanine or polyleucine, and further transformations of the epoxide products.

Audit in the management of T3 fixed-cord laryngeal cancer.

PURPOSE: To determine results of various treatments for T3 fixed-cord lesions and the subset T3 glottic cancer in Auckland from 1979 to 1995. PATIENTS AND METHODS: Data were collected retrospectively from a departmental database, and the notes were reviewed. Because of the difficulty in determining the subsite of some fixed-cord lesions, the entire group of T3 fixed-cord lesions was examined, and those tumors that were considered to be definitely arising from the glottis were then analyzed as a specific subset. RESULTS: Fixed-cord lesions were diagnosed in 75 patients (21 supraglottic, 54 glottic). Primary surgery (total laryngectomy) was performed on 46 patients, primary radical dose radiotherapy was undertaken on 25 patients, and four patients were treated palliatively. For T3 fixed-cord lesions, disease-specific survival for radiotherapy and surgery was 36% and 66%, respectively, and 32% and 67%, respectively, for T3 glottic lesions. For both T3 fixed-cord and T3 glottic lesions, surgery produced significantly better survival than did radiotherapy (<60 Gy; P = .0157). With radiotherapy greater than 60 Gy, cancer of the larynx has been controlled in seven of 13 patients, although only five patients are alive, with a median follow-up of 24 months (range, 12-49 months). CONCLUSION: Radiotherapy less than 60 Gy produced markedly inferior results to surgery for T3 fixed-cord lesions and T3 glottis in Auckland. Radiotherapy at more than 60 Gy shows promise, but an ongoing audit is essential to ensure that survival is similar to surgery and to that reported by those promoting organ-preservation protocols.

Preservation of the great auricular nerve during parotidectomy.

The great auricular nerve is routinely divided during the operation of parotidectomy, however, some surgeons have suggested that preserving the posterior branches reduces the area of post-operative anaesthesia. A prospective study was performed comparing the area of anaesthesia and hypoaesthesia in patients undergoing parotidectomy. In 20 patients the great auricular nerve was preserved and in 11 it was sacrificed. Mapping of the area of sensory loss at 2 weeks, 3, 6, 9 and 12 months showed that there was no difference between the two groups. The area of sensory loss decreased in an exponential fashion in both groups. The majority of the change occurred within 6 months. We conclude that preservation of the posterior branches of the great auricular nerve is unnecessary.

Manometric rhinometry: a new method of measuring the volume of the air in the nasal cavity.

Almost all the pathological and physiological process that effect the nose will change the volume of the airspace within it. This volume has previously been difficult to measure but a new method that calculates this space has been developed. A mechanical model was built to test the physical parameters involved in making volume measurements. The model demonstrated that a model sinus could be detected if the ostium was only 0.5 mm in diameter. It also showed that a mathematical model which described the volume of the space could be constructed. In vivo experiments showed that nasal volume can be measured in children as young as 4. In children, nasal volume correlates with age, height, and weight. They had a low coefficient of variation (7.1%) and a high test-retest correlation (r = 0.94). Adult nasal volume averaged 138 ml. The method is sensitive enough to detect the decongestant effect of xylometazoline in a group of 17 healthy volunteers (p < 0.01). There is no significant difference in the sensitivity to detect the decongestant effect of xylometazoline when compared with active anterior rhinometry, nasal peak flow, and acoustic rhinometry (range 80-95%).

A comparison of the sensitivity of manometric rhinometry, acoustic rhinometry, rhinomanometry and nasal peak flow to detect the decongestant effect of xylometazoline.

A study has been undertaken to compare the sensitivity of manometric rhinometry, rhinomanometry, nasal peak flow and acoustic rhinometry to detect the decongestant effect of xylometazoline. Twenty healthy volunteers were investigated before and after decongestion. The sensitivity of all four methods varied from 80 to 95%. These differences were not significant. Manometric rhinometry, a new method of investigating nasal physiology, is as sensitive as more established methods.

The nasal volume of children as measured by Manometric Rhinometry.

A new method of measuring nasal volume has been developed called 'Manometric Rhinometry'. We describe the principle behind its use and present the results of measuring two groups of normal children aged 4-10. The total volume of the nasal cavity, paranasal sinuses and postnasal space in these children averaged 81 ml in 4-year olds and 140 ml in 10-year olds when measured using an open cell foam plug. Where a rigid nasal tip was used the volume averaged 67 ml in 4-year olds rising to 99 ml in 8-year olds. Correlation with age, weight, height and head circumference showed the greatest correlation with height (r = 0.66). Multiple regression analysis did not add further explanatory power.

Abnormalities of the paranasal sinuses in patients with nasopharyngeal carcinoma: a computed tomographic study.

A retrospective study of computed tomography scans of the paranasal sinuses of 131 control subjects in Hong Kong revealed minor mucosal abnormalities in more than half of the ethmoid sinuses. Major abnormalities were present in seven per cent of maxillary, five per cent of anterior ethmoid and four per cent of posterior ethmoid sinus. In 85 patients with nasopharyngeal carcinoma the prevalence of minor mucosal abnormalities in the sinuses was similar to that of the control group but major mucosal abnormalities were significantly more common in the anterior and posterior ethmoids at 15 per cent and 21 per cent of the respective sinuses (p < 0.001).

The paranasal sinuses before and after radiotherapy for nasopharyngeal carcinoma: a computed tomographic study.

A study comparing the pre- and post-radiotherapy computed tomographic scans of patients treated for nasopharyngeal carcinoma revealed that the incidence of major mucosal abnormality was significantly increased and approximately doubled after radiotherapy. The most significant factor predicting major mucosal abnormality after radiotherapy was the presence of tumour in the sinus before treatment. In the maxillary sinus there was significant association of major mucosal abnormality before and after radiotherapy although this was not so for the other sinuses. The mucosal changes observed were evident as early as six months after radiotherapy.

Manometric rhinometry.

A new method of measuring nasal volume is described. It works by extracting air from a closed cavity and measuring the resultant pressure change. To validate this method in the nose, 17 healthy volunteers were examined before and after application of xylometazoline. The apparent volume before decongestion was a mean of 204 ml. After decongestion the average volume was 228 ml. The difference is highly significant (P < 0.01). We conclude that manometric rhinometry is a valid method of investigating the nose and sinuses.

The Glasgow benefit plot used to assess the effect of bilateral stapedectomy.

The Glasgow benefit plot has encouraged surgeons to look at the results of their surgery from a more functional standpoint rather than in purely technical terms. Our aim was to use the plot to examine the efficacy of second side stapedectomy. A retrospective study of 17 second side stapedectomies showed that the addition of the second operation significantly increased the chances of achieving at least one 'normal' hearing ear and made 'normal' and symmetrical hearing possible.

Fibromatosis of the parapharyngeal space.

Tumours of the parapharyngeal space are not common. The majority arise from the deep lobe of the parotid gland or neurovascular structures. We describe a case of fibromatosis, which has not previously been reported at this site.

Detection of the tumour suppressor gene p53 in nasopharyngeal carcinoma in Hong Kong Chinese.

This study has investigated the expression of the p53 tumour suppressor gene in 41 cases of primary nasopharyngeal carcinomas (NPC) using the p53 monoclonal antibody BP53-12. Moderate p53 expression was found in 54% and strong expression in 12% of the specimens. There was no correlation between p53 expression and any of the clinicopathological parameters or survival. Surprisingly, three research groups have investigated p53 mutations in NPC and found no fresh tumour specimens to contain p53 mutations in exons 4-8 of the gene. It may be argued that as p53 overexpression has been demonstrated in 70% of the patients investigated in this study, that the mutations lie outside the 4-9 exon region. We are in the process of testing this hypothesis.

The detection of the c-myc and ras oncogenes in nasopharyngeal carcinoma by immunohistochemistry.

Forty-one paraffin embedded specimens of primary nasopharyngeal carcinoma (NPC) were examined to investigate the expression of c-myc and ras oncogenes. Sections were stained with the monoclonal antibodies myc 1-9E10 or ras Y13-259 and binding was detected using the ABC method. The intensity of staining for each tumour was assessed as nil, moderate or intense. The results indicated that 9 (22%) had intense staining for the c-myc oncogene, 28 (68%) had moderate staining and only 4 (10%) showed no staining. For the ras oncogene, 8 (19%) had intense staining, 22 (54%) moderate staining and 11 (27%) showed no staining. The patient's clinical data indicated no correlation between the expression of either c-myc or ras p21 and age, sex, smoking, tumour stage, antibody titre to EBV, or family history. No correlation was found between ras p21 expression and survival; however, overexpression of the c-myc oncogene correlated with a poor prognosis (p < 0.05). This study is consistent with investigations demonstrating that c-myc expression correlates with poor survival in head and neck tumours.

Current practice of stapedectomy in Great Britain.

Since the introduction of stapedectomy with reconstruction of the ossicular chain to Great Britain, many modifications in practice have taken place. The changes include patient selection, operative technique and the type of prosthesis used, as well as the number of operations performed yearly. The aim of this study is to attempt to establish the actual practice among British otolaryngology consultants by means of a simple questionnaire. Two hundred (50.3%) forms were analysed anonymously. The study confirms the decrease in the number of operations performed annually, the absence of centralization for this type of surgery in Great Britain and also demonstrated the trends towards stapedotomy and the practice of bilateral surgery amongst younger consultants.