Pilomatrixoma in the parotid region

Pilomatrixoma is a benign neoplasm of the hair follicle that may present to the otolaryngologist as a palpable swelling in the head and neck area. The correct diagnosis may be difficult to confirm when it presents in the region of the parotid. The use of fine needle aspiration cytology (FNAC) and diagnostic imaging may help confirm the diagnosis. The correct treatment is surgical. However, should the tumour recur then the possibility of malignancy should be considered.

The pro region of Toxoplasma ROP1 is a rhoptry-targeting signal

The rhoptries of Toxoplasma gondii are regulated secretory organelles involved in the invasion of host cells. Rhoptry proteins are synthesised as pre-pro-proteins that are processed first to pro-proteins upon entrance into the secretory pathway, then processed again to their mature forms late in the secretory pathway. The pro-mature processing site of the rhoptry protein ROP1 has been determined, paving the way for understanding the role of the pro region in rhoptry protein function. We demonstrate here that the ROP1 pro region is sufficient for targeting a reporter protein (amino acids 34-471 of the Trypanosoma brucei VSG117 protein) to the rhoptries. These results, together with our previous work showing that rhoptry targeting is unaffected by deletion of the pro region, indicate that the ROP1 protein contains at least two signals that can function in rhoptry targeting.

Benign salivary gland disease

The majority of benign clinical problems that present affect the major salivary glands--parotid and submandibular. However, there are numerous minor salivary glands located in the mucosa of the head and neck which have the same predilection to the same diseases that affect the major glands but to a lesser frequency.

Distant metastases from salivary glands cancer

Patients who present with malignant salivary glands should at their initial assessment have an X-ray of the chest to exclude the possibility of distant metastases. Patients who have other symptoms, bone pain etc., should be appropriately investigated. The likelihood of patients developing distant metastases is associated with high-grade tumors, most commonly adenoid cystic carcinoma, high-grade mucoepidermoid carcinoma, salivary duct carcinoma and tumors sited in the submandibular gland, posterior tongue and pharyngeal tumors. Patients who have had a high-grade tumor treated and survived without locoregional recurrence have the same risk of developing distant metastases as those patients who have locoregional recurrence. Other histological types of salivary tumors are associated with a lower risk of developing distant metastases but a real risk remains lifelong. It is recommended that all patients who have a malignant salivary gland tumor treated, any histology, should be followed up and clinically assessed at least once every 12 months for life.

MIB-1 and p53 expression in radiotherapy-resistant T1aN0M0 glottic squamous cell carcinoma

Radiotherapy of T1aN0M0 glottic carcinoma results in a local control rate of 80-94%. This homogenous group, which is the earliest recognisable invasive malignancy in the head and neck region, provides a 'unique model' for studying possible biological markers of radiosensitivity. p53 and MIB-1 were investigated as possible markers of radiosensitivity in such a group. In all, 107 patients with T1aN0M0 glottic squamous cell carcinoma treated with radiotherapy were identified. Cases not responsive to radiotherapy were compared with matched radiosensitive controls by immunohistochemistry using monoclonal primary antibodies to MIB-1 (n = 18; controls = 10) and p53 (n = 6; controls = 11). No significant difference in p53 expression was noted between the two groups (P = 0.73). A greater MIB-1 expression was found in the radiosensitive group but only a trend towards significance was observed (P = 0.06). MIB-1 is a potential marker of radiosensitivity. A larger multicentre study is required for a more definitive answer.

A randomised clinical trial of turbinectomy for compensatory turbinate hypertrophy in patients with anterior septal deviations

Turbinectomy is performed at the time of nasal septal surgery by many otolaryngologists. One reason given for this procedure is the presence of a hypertrophied contralateral inferior turbinate. A randomised trial was undertaken to evaluate the relief of nasal obstruction following contralateral turbinectomy with septal surgery. Patients presenting with nasal obstruction who had a unilateral septal deviation and contralateral inferior turbinate enlargement were prospectively randomized to contralateral turbinectomy or no turbinate surgery at the time of septal surgery. Questionnaires and active anterior rhinomanometry were used for evaluation. Twenty-six patients (mean age 31 years) demonstrated a reduction in subjective and objective measures of nasal obstruction (P < 0.05) 8 weeks after operation. There was no intergroup difference, the median total decongested nasal resistance postoperatively in the non-turbinectomized patients was 0.17 kPal-1 s and 0.21 kPal-1 s in the turbinectomized patients. Contralateral inferior turbinectomy does not add to the relief of nasal obstruction beyond that attained by septal surgery in these patients.

Toxoplasma gondii homologue of plasmodium apical membrane antigen 1 is involved in invasion of host cells

Proteins with constitutive or transient localization on the surface of Apicomplexa parasites are of particular interest for their potential role in the invasion of host cells. We describe the identification and characterization of TgAMA1, the Toxoplasma gondii homolog of the Plasmodium apical membrane antigen 1 (AMA1), which has been shown to elicit a protective immune response against merozoites dependent on the correct pairing of its numerous disulfide bonds. TgAMA1 shows between 19% (Plasmodium berghei) and 26% (Plasmodium yoelii) overall identity to the different Plasmodium AMA1 homologs and has a conserved arrangement of 16 cysteine residues and a putative transmembrane domain, indicating a similar architecture. The single-copy TgAMA1 gene is interrupted by seven introns and is transcribed into an mRNA of approximately 3.3 kb. The TgAMA1 protein is produced during intracellular tachyzoite replication and initially localizes to the micronemes, as determined by immunofluorescence assay and immunoelectron microscopy. Upon release of mature tachyzoites, TgAMA1 is found distributed predominantly on the apical end of the parasite surface. A approximately 54-kDa cleavage product of the large ectodomain is continuously released into the medium by extracellular parasites. Mouse antiserum against recombinant TgAMA1 blocked invasion of new host cells by approximately 40%. This and our inability to produce a viable TgAMA1 knock-out mutant indicate that this phylogenetically conserved protein fulfills a key function in the invasion of host cells by extracellular T. gondii tachyzoites.

Non-Hodgkin's lymphoma of the sinonasal tract

OBJECTIVES

A review of the presenting features, management, and outcome of extranodal non-Hodgkin's lymphoma (NHL) of the sinonasal tract during a 10-year period in Nottingham, UK.

STUDY DESIGN

Twenty-four patients received a diagnosis of extranodal NHL of the nasal cavity, paranasal sinuses, or both, from 1987 to 1996. The patients' data were collected prospectively in the Nottinghamshire Lymphoma Registry.

METHODS

All patients' records and their histology were reviewed along with data entered into the Nottinghamshire Lymphoma Registry, noting the patient's age, sex, presenting symptoms and signs, staging, computed tomography findings, histology, treatment, complications, and outcome.

RESULTS

The 24 patients with extranodal NHL of the sinonasal tract represent 1.63% of the 1,457 patients with NHL seen in the 10-year period of this study in Nottinghamshire. The median age was 72 years (range, 42-96 y), with a male dominance (male-to-female ratio: 15:9). Most patients presented with nonspecific nasal symptoms such as nasal obstruction and epistaxis. Only one patient had a relapse involving the central nervous system after treatment. All the histology was reviewed and showed a predominance of large B-cell subtype (21 patients). The overall 5-year survival was 40% (95% CI, 19%-61%) and 33% for 10-year (95% CI, 12%-54%). The cause-specific survival at 5 years and 10 years was 62% (95% CI, 39%-86%).

CONCLUSIONS

A high degree of suspicion and appropriate use of computed tomography scans and surgical biopsy are the keys to the management of NHL.

Presence of a member of the mitochondrial carrier family in hydrogenosomes: conservation of membrane-targeting pathways between hydrogenosomes and mitochondria

A number of microaerophilic eukaryotes lack mitochondria but possess another organelle involved in energy metabolism, the hydrogenosome. Limited phylogenetic analyses of nuclear genes support a common origin for these two organelles. We have identified a protein of the mitochondrial carrier family in the hydrogenosome of Trichomonas vaginalis and have shown that this protein, Hmp31, is phylogenetically related to the mitochondrial ADP-ATP carrier (AAC). We demonstrate that the hydrogenosomal AAC can be targeted to the inner membrane of mitochondria isolated from Saccharomyces cerevisiae through the Tim9-Tim10 import pathway used for the assembly of mitochondrial carrier proteins. Conversely, yeast mitochondrial AAC can be targeted into the membranes of hydrogenosomes. The hydrogenosomal AAC contains a cleavable, N-terminal presequence; however, this sequence is not necessary for targeting the protein to the organelle. These data indicate that the membrane-targeting signal(s) for hydrogenosomal AAC is internal, similar to that found for mitochondrial carrier proteins. Our findings indicate that the membrane carriers and membrane protein-targeting machinery of hydrogenosomes and mitochondria have a common evolutionary origin. Together, they provide strong evidence that a single endosymbiont evolved into a progenitor organelle in early eukaryotic cells that ultimately give rise to these two distinct organelles and support the hydrogen hypothesis for the origin of the eukaryotic cell.

Competition and protease sensitivity assays provide evidence for the existence of a hydrogenosomal protein import machinery in Trichomonas vaginalis

Hydrogenosomes are double membrane bounded redox organelles found in a number of amitochondriate protists and fungi. They are involved in carbohydrate metabolism and ATP synthesis and thus resemble mitochondria. Molecular analysis of the hydrogenosomal heat shock proteins Hsp70, Hsp60 and Hsp10 in Trichomonas vaginalis, one of the deepest-branching eukaryotes known to date, has revealed that these group exclusively with mitochondrial heat shock proteins. This finding indicates strongly that a progenitor organelle which gave rise to contemporary mitochondria and hydrogenosomes existed early in eukaryotic life. This hypothesis is further supported by similarities of hydrogenosomal and mitochondrial biogenesis. It was shown that T. vaginalis hydrogenosomal proteins are synthesized on free ribosomes in the cytosol with an N-terminal presequence that carries targeting information and is cleaved upon import into the organelle. Furthermore, as in mitochondrial import, hydrogenosomal protein import requires ATP, an electrochemical transmembrane potential and cytosolic protein factor(s). Here we demonstrate that inhibition of hydrogenosomal protein import occurs (i) in the presence of a synthetic presequence peptide and (ii) after pretreatment of hydrogenosomes with the protease trypsin. Trypsin pretreatment affects two hydrogenosomal membrane proteins of 31 and 70 kDa, respectively. Thus, we present evidence that import is saturable and that proteinaceous hydrogenosomal import receptor(s) exist. These results are a first step towards a characterization of the hydrogenosomal import machinery which should provide further insights into the relationship of hydrogenosomes and mitochondria and the evolution of protein targeting into organelles of endosymbiotic origin.

Pharyngeal pouch carcinoma: real or imaginary risks?

Pharyngeal pouch or Zenker's diverticulum presents to the otolaryngologist with symptoms of dysphagia. As supported by the published literature, the condition is more frequently seen in Northern Europe, especially the United Kingdom, than elsewhere in the world. The cause of the reported increased incidence in the United Kingdom is not known, but may be dietary. Surgical management is the treatment of choice and is directed at the cricopharyngeus muscle by either an external or an internal approach. There is a real risk of carcinoma or carcinoma in situ developing in a treated or untreated pharyngeal pouch. Excision of the pouch sac is recommended in younger patients, less than 65 years, and in patients who have a large pouch. If endoscopic diverticulotomy is performed, then long-term patient symptom follow-up is to be advocated.

Frey's syndrome following parotidectomy: prevention using a rotation sternocleidomastoid muscle flap

The benefit of using a sternocleidomastoid flap following parotidectomy to reduce the incidence of symptomatic gustatory sweating (Frey's syndrome) was reviewed. A retrospective study was undertaken to review subjective and objective symptoms of Frey's syndrome in two groups of patients, one of whom had undergone superficial parotidectomy with a sternocleidomastoid flap rotated at the time of surgery and a second group of patients who had undergone a standard superficial parotidectomy. A total of 22 patients, randomly sampled and willing to attend, were evaluated postoperatively, at a median time from surgery of 42 months (range 23-82 months) in the non-flap group and 44 months (range 14-66 months) in the flap group, by Minor's starch iodine test. In the 11 patients who had a sternocleidomastoid flap rotated, two had evidence of gustatory sweating. Of the 11 that had not undergone sternocleidomastoid flap rotation, nine patients showed evidence of gustatory sweating (P < 0.05, chi 2 test). There were two patients in total who had clinical symptoms of Frey's syndrome and both of these had not undergone flap rotation at the time of parotidectomy.

Identification of the pro-mature processing site of Toxoplasma ROP1 by mass spectrometry

The rhoptries are specialized secretory organelles that function during host cell invasion in the obligate intracellular parasite Toxoplasma gondii. All T. gondii rhoptry proteins studied to date are synthesized as pro-proteins that are then processed to their mature forms. To understand the role of the pro region in rhoptry protein function, we have precisely defined the processing site of the pro-region of the rhoptry protein ROP1. Efforts to determine such processing sites have been prevented by blocked N-termini of mature proteins isolated from T. gondii. To overcome this problem, we have used an engineered form of ROP1 and mass spectrometry to demonstrate that proROP1 is processed to its mature form between the glutamic acid at position 83 and alanine at position 84. These data also show that mature ROP1 lacks substantial post-translational modifications, a result which has important implications for targeting of rhoptry proteins.

Treatment of the patient with upper airway obstruction caused by cancer of the larynx

The treatment of a patient with imminent airway obstruction caused by a malignant tumor of the larynx is an uncommon clinical problem. These cases need to be evaluated, diagnosed, and managed with care, skill, speed, and above all, appropriateness of intervention. Three methods are available to control the airway: tracheostomy, emergency laryngectomy, and controlled tracheal intubation with or without tumor debulking. Two groups of patients had their airways managed either by tracheostomy and delayed elective surgery or by emergency laryngectomy. There was no survival advantage between the groups, and no increased risk of stomal recurrence was demonstrated. If time permits, the patient is considered suitable, and adequate anesthetic and surgical instrumentation is available, it is currently recommended that the obstructing laryngeal tumor be debulked by cold-steel or, preferably, CO2 laser and that the emergency situation be stabilized and the definitive treatment of the patient be converted to an elective procedure without the need to create a tracheostomy.

Nucleocapsid protein zinc-finger mutants of simian immunodeficiency virus strain mne produce virions that are replication defective in vitro and in vivo

All retroviruses (except the spumaretroviruses) contain a nucleocapsid (NC) protein that encodes one or two copies of the Zn2+-finger sequence -Cys-X2-Cys-X4-His-X4-Cys-. This region has been shown to be essential for recognition and packaging of the genomic RNA during virion particle assembly. Additionally, this region has been shown to be involved in early infection events in a wide spectrum of retroviruses, including mammalian type C [e.g., murine leukemia virus (MuLV)], human immunodeficiency virus type 1 (HIV-1), Rous sarcoma virus, and other retroviruses. Mutations in the two Zn2+-fingers of the NC protein of simian immunodeficiency virus strain Mne [SIV(Mne)] have been generated. The resulting virions contained the normal complement of processed viral proteins with densities indistinguishable from wild-type SIV(Mne). All of the mutants had electron micrograph morphologies similar to those of immature particles observed in wild-type preparations. RNA packaging was less affected by mutations in the NC protein of SIV(Mne) than has been observed for similar mutants in the MuLV and HIV-1 systems. Nevertheless, in vitro replication of SIV(Mne) NC mutants was impaired to levels comparable to those observed for MuLV and HIV-1 NC mutants; replication defective NC mutants are typically 10(5)- to 10(6)-fold less infectious than similar levels of wild-type virus. One mutant, DeltaCys33-Cys36, was also found to be noninfectious in vivo when mutant virus was administered intravenously to a pig-tailed macaque. NC mutations can therefore be used to generate replication defective virions for candidate vaccines in the SIV macaque model for primate lentiviral diseases.

ENT pathology and diplopia

ENT pathology causes diplopia in a minority of patients. Because the various ENT conditions that can produce diplopia are relatively unusual they often escape early detection. We describe the various ENT disorders that can produce diplopia and illustrate this with our experience between 1992 and 1998. We wish to emphasise the benefit which can be obtained from undertaking an ENT history and examination in arriving at the correct diagnosis.