Role of Phosphate Transport System Component PstB1 in Phosphate Internalization by Nostoc punctiforme.

In bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacterium Nostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified. pstB1 was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined that pstB1 mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed when pstB2, pstB3, and pstB4 mRNA levels increased, particularly in cells starved of phosphate. The overexpression of pstB1 increased phosphate uptake by N. punctiforme and was shown to functionally complement the loss of PstB in E. coli PstB knockout (PstB-) mutants. The knockout of pstB1 in N. punctiforme did not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in the pstB2, pstB3, and pstB4 mRNA levels. This study provides novel in vivo evidence that PstB1 plays a functional role in phosphate uptake in N. punctiforme IMPORTANCE: Cyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the synthesis of active uptake systems. The Pst phosphate transport system is one such system, responsible for the internalization of phosphate when cells are in phosphate-limited environments. Our investigations reveal the presence of multiple Pst phosphate uptake systems that exist across three distinct operons in Nostoc punctiforme and functionally characterize the role of the gene product PstB1 as being crucial for the maintenance of phosphate accumulation. We demonstrate that the genes pstB2, pstB3, and pstB4 show alterations in expression to compensate for the deletion of pstB1 The overall outcomes of this work provide insights as to the complex transport mechanisms that exist in cyanobacteria like N. punctiforme, allowing them to thrive in low-phosphate environments.

Primary, combined, atypical carcinoid and squamous cell carcinoma of the larynx: a new variety of composite tumour.

OBJECTIVE: We report the first case of a laryngeal composite tumour consisting of a squamous cell carcinoma combined with an atypical carcinoid. METHODS: Case report and review of the literature concerning laryngeal composite tumours. RESULTS: Primary laryngeal carcinoma is the most common malignancy of the upper aerodigestive tract. The vast majority are of the squamous cell type. Primary neuroendocrine neoplasms represent a rare, heterogeneous subset of laryngeal malignancies, comprising typical carcinoid, atypical carcinoid, small cell carcinoma and paraganglioma. Primary combined neuroendocrine and squamous cell carcinoma of the larynx is even more rarely encountered, with only 14 publications of this so-called composite tumour to date. In each case, the neuroendocrine component has been small cell carcinoma. CONCLUSION: The treatment of primary neoplasms comprising more than one histological type is tailored to the most biologically aggressive tumour. Accurate diagnosis of the histological nature of laryngeal composite tumours is imperative to ensure optimal therapy.

A study of olfactory testing in patients with rhinological pathology in the ENT clinic.

BACKGROUND: Despite the common occurrence of rhinological pathology presenting to the ENT clinic, routine testing of olfactory ability is rarely performed. OBJECTIVES: The aim of this study was to determine the role of routine olfactory testing. METHODS: This was a prospective study conducted in the outpatient clinic of a district general hospital. Patients presenting with rhinological complaints had their olfactory status assessed using the combined olfactory test (COT) before and after rhinological surgery. RESULTS: Eighty patients (56 men, 24 women) had tests completed over a 12-month period. Patients assessed mostly had nasal polyposis, chronic rhinosinusitis or septal deformity. 83% of patients had either a complaint of olfactory disturbance or a COT score of 6 or less, or had both; but correlation between symptoms and scores was poor. Post-operative COT scores showed significant improvement (p = 0.02) with post-septoplasty patients showing the most significant improvement as a group (p = 0.001). CONCLUSIONS: Olfactory disturbance is very common in rhinological pathology and the patient's history alone cannot be relied upon. Simple olfactory assessment, such as with the combined olfactory test, is easy to perform and cheap to use and should be a commonly used resource in the ENT clinic. Formal testing can help to document any pre-existing olfactory loss and any post-operative changes as well as detecting unreported hyposmia.

Management of retrosternal goitres: results of early surgical intervention to prevent airway morbidity, and a review of the English literature.

We present our experience and also review the world literature on the management of retrosternal goitres (RSGs). There is now irrefutable evidence that almost all RSGs will continue to grow and eventually cause airway compression. We describe the diagnosis, investigation and surgical approach to the management of this condition.

Research tissue banking in otolaryngology: organization, methods and uses, with reference to practical, ethical and legal issues.

The field of molecular biology is an important part of research into neoplastic conditions. Much of this research requires access to human tissue samples, which may need to be collected and stored in a specific way, according to the type of study for which they are intended. Anonymous clinical information about the samples enables researchers to apply results to different patient groups. Access to stored tissues is particularly important in head and neck disease research as many neoplastic conditions affecting this area have a relatively low incidence. Consequently, it may take a long time to build up enough individual cases to make a study worthwhile. We describe here the current legal, ethical and practical issues of research tissue banking, with regard to head and neck disease.

The myth of tracheomalacia and difficult intubation in cases of retrosternal goitre.

Although it is widely believed that management of the airway is difficult in surgery for retrosternal goitre, a review of the literature, revealing management of 1969 patients with retrosternal goitre, provided scant evidence of difficult intubation or post-operative tracheomalacia resulting in tracheal collapse. This was reflected in our own series of 18 thyroidectomies for retrosternal goitre performed at our hospitals.

Reidel's thyroiditis and Tolosa-Hunt syndrome, a rare association.

A previously undescribed association of Reidel's thyroiditis with Tolosa-Hunt syndrome is reported. A 33 year-old Caucasian female presented with a two-year history of painful progressive goitre, histologically a Reidel's thyroiditis. She underwent left partial thyroidectomy. Post-operatively she developed severe right retro-orbital pain, right temporal headache and a partial right occulomotor nerve palsy. A diagnosis of Tolosa-Hunt syndrome was made. Some important aspects of this case are discussed.

Use of a disposable electrode for recurrent laryngeal nerve monitoring.

Our experience with a non-invasive, disposable electrode for intra-operative identification and monitoring of the recurrent laryngeal nerve is described. The electrode system, while simply attached to the endotracheal tube, acts as a laryngeal surface electrode and detects electromyographic activity of the intrinsic laryngeal muscles when the recurrent laryngeal nerve is stimulated. We have successfully used this electrode to monitor 19 recurrent laryngeal nerves in 15 patients who have undergone partial or total thyroidectomy. We feel that this device can be useful particularly in cases of re-exploration and malignancies of the thyroid gland.

Non-recurrent laryngeal nerve: identification during thyroid surgery.

The non-recurrent course of the inferior laryngeal nerve is a rare anomaly. The incidence varies from 0.3 to 4% on the right side. It is extremely rare on the left side. The awareness of such an anomaly is essential as the risk of damage to the nerve is higher during thyroid surgery. Two cases of non-recurrent laryngeal nerve are reported, and the embryology and method of identification are discussed.

Long-term results of the use of cultured autologous epithelial cell grafting to mastoid cavities.

Thirty-nine patients (42 ears) who have had a cultured autologous epithelial cell graft technique to a continuously discharging mastoid cavity have been evaluated to determine the continued effectiveness of this procedure. A postal questionnaire indicated a 58% improvement in both the smell and quantity of discharge, and our conclusion is that this is a very effective measure to provide extended symptomatic improvement in this troublesome condition.

Lipoma of the parotid gland presenting with facial palsy.

Facial palsy in the presence of ipsilateral parotid tumour is considered to be pathognomonic of malignancy. However, benign neoplasms and inflammatory lesions of the parotid gland have been reported to present with facial palsy. A case of lipoma of the parotid gland associated with partial facial paralysis is reported. Lipomas are very rarely seen in this site. To our knowledge, a lipoma of the parotid producing facial paralysis has not been described previously. This report highlights the difficulties in pre-operative diagnosis and management of such a lesion.

Topical active H1-antihistamines and their effect on nasal airway resistance.

The introduction of a topically active H1-antihistamine nasal spray Azelastine, has given an extra dimension in the management of allergic rhinitis. The drug acts rapidly and avoids the systemic adverse effects of antihistimines. An objective prospective study was performed to detect the effect of Azelastine nasal spray on nasal airway resistance. Twelve healthy adult volunteers with no rhinological problems were included in the study. Nasal cavities were sprayed with 280 micrograms (two puffs) of Azelastine nasal spray and the nasal airway resistance was measured with anterior rhinomanometry at intervals of 30 minutes for up to two hours. Our study has shown a statistically significant increase in the total nasal airway resistance following the use of Azelastine nasal spray in the absence of a subjective change in nasal airway resistance. There are substances when inhaled which can cause subjective improvement in nasal airway patency without changing the measured nasal airway resistance. However this medication gives no subjective change in nasal airway patency in spite of increasing nasal airway resistance.

Long-term results of mastoid cavities grafted with cultured epithelium prepared from autologus epidermal cells to prevent chronic otorrhea.

Chronic otorrhea and recurrent infection from open mastoid cavities are common and troublesome clinical problems for which there is no very satisfactory treatment. The authors have previously described a simple procedure to solve this problem, using autologous cultured keratinocyte layers grafted onto the unepithelialized open mastoid cavities. All procedures are carried out on an outpatient basis without anesthesia, except for local anesthesia for the skin biopsy. Twenty-six patients with 28 "difficult" mastoids, in which otorrhea had been present from 2 to 32 years, have been grafted with a follow-up period varying from 10 to 18 months. Seventeen mastoid cavities became symptom-free as a result of this technique. There were 4 failures, and partial success was shown in 7 cavities as judged by both the patient and by clinical examination.

Dominant maxillary artery as a cause of failure in maxillary artery ligation for posterior epistaxis.

Ligation of the maxillary artery is a logical and effective method for the arrest of severe uncontrollable posterior epistaxis. The failure rates for arrest of haemorrhage are given in the literature as 10-13%. In our centre, over the last 9 years, 23 patients have undergone maxillary artery ligation to control epistaxis without a failure. Bilateral maxillary artery ligation was carried out whenever the maxillary artery of the bleeding side was found to be of small diameter. To investigate whether there is an asymmetry in the size of the maxillary arteries we performed 13 cadaveric dissections. In 6 of the cadavers one maxillary artery was significantly larger than the other. This fact has hitherto not been observed by otolaryngologists or anatomists. Failure to arrest haemorrhage may have resulted from ligation of the non-dominant maxillary artery with consequent opening of cross-anastomoses from the dominant side.

Treatment of chronic mastoiditis by grafting of mastoid cavities with autologous epithelial layers generated by in vitro culture of buccal epithelium.

Autologous cultured epithelial layers were established from biopsies from the mucosa of the cheek, a non-keratinizing region of the oral cavity. These were grafted to the unepithelialized mastoid cavities of nine patients with chronic mastoiditis and severe otorrhoea varying from two to 30 years' duration. All procedures were performed on an out-patient basis, with no anaesthesia except for topical anaesthesia for the mucosal biopsy. In seven of the patients the grafts took well, with complete resolution of the otorrhoea for a minimum follow-up period of eight months. In one patient there was a partial take of the graft with substantial improvement in the rate of discharge. The mastoid cavities of two patients were biopsied five months after grafting, and demonstrated a stratified squamous epithelium, with keratinization of the epithelium clearly evident.

Childhood haemangiomas of the head and neck.

Haemangiomas of the head and neck in children may be of several histological types, the clinical course depending on the group to which the haemangioma belongs. Treatment may be required if the haemangioma interferes with the airway, as in the subglottic group, or if the lesion becomes ulcerated with subsequent haemorrhage, as in capillary cavernous haemangiomas. Most haemangiomas require no immediate treatment as they involute spontaneously, though parental reassurance will be of paramount importance. Those lesions which persist may be amenable to treatment at a later date, the laser probably offering the best long-term results in terms of cosmesis as in the case of port-wine stains. Superselective embolization is becoming the treatment of choice for arterial haemangiomas. This paper is designed to clarify the histological and clinical features of these tumours and their management in view of considerable confusion in the literature encountered in our study.

Massive haemorrhage from the vallecula: a diagnostic difficulty. Case report.

A case is presented of massive bleeding from a vessel in the vallecula. This was confused with haemoptysis and haematemesis. The bleeding may have resulted from trauma to the vessel during intubation for emergency surgery. 25 units of blood were transfused before the site of the bleeding was identified and controlled by diathermy coagulation.

Management of posterior epistaxis with the use of the fibreoptic nasolaryngoscope.

Posterior epistaxis is usually treated by repeated nasal packing and in failed situations by ligation of feeding arteries with considerable morbidity and mortality. The most logical approach should be location of the bleeding site and arrest of haemorrhage by local treatment. The exact location of the bleeding area can be identified in actively bleeding noses with the fibreoptic naso-laryngoscope and the bleeding arrested by chemical, or thermal cautery and in failed situations by using small nasal packs confined to the bleeding site. This approach to the management of posterior epistaxis is effective and reduces the duration of hospital stay. It significantly reduces the discomfort to the patient. The current practice of indiscriminate blind nasal packing in the hope of arresting nasal haemorrhage by incidental pressure on the bleeding site should be re-evaluated.