Identification of the accessory nerve by its relationship to the great auricular nerve

OBJECTIVES

To describe the use of the great auricular nerve as a 'road map' for locating the accessory nerve in the anterior and posterior triangle, in comparison with other methods described in the literature.

DESIGN

A review of the literature using Medline and Embase searches was performed. Illustrative photographs were taken from consenting, elective patients.

RESULTS

Various methods have been described, using different anatomical landmarks. We describe a new method, based on the fact that the great auricular nerve runs, with relation to the edges of the sternocleidomastoid muscle, 1 cm superior to the accessory nerve anteriorly and 1 cm inferior posteriorly.

CONCLUSIONS

This is a reliable and safe method, used by the senior authors in their extensive work as head and neck and skull base surgeons. It allows the accessory nerve to be located in both the anterior and posterior triangle. This avoids the inherent dangers of following the nerve's tortuous course through the sternocleidomastoid.

Validation and application of capillary electrophoresis for the analysis of lidocaine in a skin tape stripping study

A fast and simple capillary zone electrophoresis method was developed and validated for the determination of lidocaine in skin using tape samples. Separation was performed in a 350 mm (265 mm to window) x 50 microm i.d. fused silica capillary using a background electrolyte of phosphoric acid-Tris pH 2.5. The extraction of lidocaine from tape samples was achieved using methanol, which was diluted to 50% with water before injection. Procaine was the internal standard. The migration times for procaine and lidocaine were 2.9 and 3.2 min, respectively. The limit of quantification for lidocaine was 50 microg, with signal to noise ratio greater than 10. The calibration curve was linear from 50 to 1000 microg with r(2) greater than 0.99. The CV for both within- and between-assay imprecision and the percentage of inaccuracy for the quality control samples including lower and upper limits of quantitation were <or=2% and <or=14%, respectively. The absolute recovery of lidocaine was >97%. The accuracy and selectivity of this method allowed the measurement of lidocaine in tape samples obtained from a skin tape stripping study of local anesthetics in healthy subjects.

Update on the use of ciclosporin in immune-mediated dermatoses

Immune-mediated dermatoses, such as psoriasis and atopic dermatitis, affect a significant proportion of the population. Although most cases are not life threatening, these diseases can have a profound effect on the sufferer's quality of life and that of their family. Systemic therapy, such as ciclosporin, is often indicated for severe or recalcitrant disease. The efficacy of ciclosporin in the treatment of psoriasis and atopic dermatitis has been established and clinical data also demonstrate its efficacy in treating less common but equally challenging conditions such as pyoderma gangrenosum, lichen planus, autoimmune bullous disease, recalcitrant chronic idiopathic urticaria and chronic dermatitis of the hands and feet. The risk of potential adverse events associated with ciclosporin is greatly reduced if current treatment and monitoring guidelines are followed.

Pharmacokinetics of a new testosterone transdermal delivery system, TDS-testosterone in healthy males

AIMS

The Transdermal Delivery System (TDS) is a liquid formulation that can be applied to the skin via a metered pump spray to deliver drug to the systemic circulation. The aims of this study were to assess the ability of the TDS preparation to deliver testosterone systemically, and to characterize the pharmacokinetic profiles of the hormone in healthy males.

METHODS

An open label, comparative, randomized placebo controlled study involving three treatments and three periods with a minimum of a 1 week washout period was conducted. Twelve healthy males received 50 mg TDS-testosterone, TDS-placebo, and 50 mg of a commercially available topical testosterone preparation (Androgel, 1% topical testosterone gel).

RESULTS

The mean AUC(0,12 h) was higher following application of TDS-testosterone (61.8 ng ml-1 h), compared with Androgel (57.7 ng ml-1 h) and TDS-placebo (50.7 ng ml-1 h. The mean Cmax (0,12 h) was similar for TDS-testosterone (6.6 ng ml-1) and Androgel (6.5 ng ml-1) and these values were higher than those for TDS-placebo (5.7 ng ml-1). Analysis of variance showed that the 90% confidence intervals on the relative difference of the ratio for the AUC(0,12 h) and the Cmax (0,12 h) between TDS-testosterone and Androgel, were contained within the bioequivalence limit (80, 125%) (Cmax 89.2, 112.3% and AUC 93.5, 120.5%). Serum testosterone concentrations were lower following TDS-Placebo and were not bioequivalent either to the gel or spray.

CONCLUSIONS

The TDS preparation was shown to deliver testosterone systemically to humans and the concentrations of the hormone in the 12 h following TDS administration were bioequivalent to an existing topical delivery gel.

Renal transplantation in Indo-Asian patients in the UK

Membership of some ethnic groups has an effect on renal transplant outcome but little is known about the impact of Indo-Asian ethnicity, despite this group's high incidence of renal disease. We compared outcomes in Indo-Asians and Caucasians at the Hammersmith Hospital (Indo-Asians, N = 46; Caucasians, N = 90), in the Long-Term Efficacy and Safety Surveillance (LOTESS) database of cyclosporin-treated renal transplant recipients (Indo-Asians, N = 254; Caucasians, N = 4262) and the National Transplant Database held by UK Transplant (Indo-Asians, N = 459; Caucasians, N = 4831). The baseline demographic and co-morbid characteristics of the two ethnic groups were comparable, save for more diabetes in the Indo-Asian community. Following transplantation, the incidence of delayed graft function and steroid-resistant acute rejection were also comparable, as were graft and patient survival (out to 5 years) and graft function. In addition, post-transplant blood pressure, levels of cholesterol and triglycerides and exposure to corticosteroids and cyclosporin were comparable. However, when patients who were not diabetic before transplantation were studied separately, there was an increased incidence of diabetes in the Indo-Asian community (Hammersmith data: Indo-Asians 10.9% vs. Caucasians 3.3%, p = 0.02; LOTESS data Indo-Asians 5.5% vs. Caucasians 1.6%, p < 0.0001). Subsequent management of this group should pursue immunosuppressive regimens less likely to impair post-transplant glucose tolerance.

Study of a combined percutaneous local anaesthetic and the TDS system for venepuncture

Transdermal Delivery System (TDS) is a liquid formulation which can be applied to the skin via a metered pump spray to deliver drug across skin. This placebo controlled, double blind trial compared anaesthetic properties of two TDS systems (TDS alpha and TDS beta) with placebo. The active and placebo treatments were applied to the dorsum of the hands, bilaterally and simultaneously for 5 min on 100 healthy volunteers. Following cannulation, pain perception was measured using the verbal rating score (VRS) and visual analogue score (VAS). Lidocaine plasma levels were assessed at 0 and 2 h. The VRS and VAS results show that TDS beta significantly decreased pain score compared to placebo (p < 0.02). Blood lidocaine at 2 h post application was also higher for TDS beta than for TDS alpha, suggesting that a 5 min application of TDS beta was effective in delivering local anaesthetic and accelerating the onset of skin anaesthesia prior to venous cannulation in adults.

The maize An2 gene is induced by Fusarium attack and encodes an ent-copalyl diphosphate synthase

Using the technique of differential display, a maize transcript was identified whose silk tissue expression is induced in the presence of the ear rot pathogen Fusarium graminearum. The 3445 nt transcript includes a 727 nt 5' untranslated leader with the potential for extensive secondary structure and represents the maize gene An2. An2 encodes a copalyl diphosphate synthase (CPS)-like protein with 60% amino acid sequence identity with the maize An1 gene product involved in gibberellin (GA) biosynthesis. Recombinant expression and functional analysis demonstrated that both AN1 and AN2 are ent-copalyl diphosphate (ent-CPP) synthases (ent-CPS). Notably, the presence of an additional ent-CPS gene is consistent with previous reports that maize GA biosynthesis can proceed in the absence of An1. In addition, northern blot analysis showed that An2 transcript levels were strongly up-regulated by Fusarium attack, with an increase in silk, husk and ear tip tissues as early as 6 h after inoculation of silk channels with spore suspensions of various Fusarium sp. Gene expression of a third maize CPS-like gene, Cpsl1, is not affected by Fusarium infection. The Fusarium-inducible nature of An2 is also consistent with a previous report that cell-free extracts from maize seedlings produce ent-CPP derived diterpenes in response to Fusarium infection. However, it is not known whether An2 is involved in defense-related secondary metabolism in addition to GA synthesis.

Time for tea, anyone?

There have been suggestions that urine samples positive for benzoylecognine, the diagnostic metabolite of cocaine, may be the result of consumption Mate de Coca, a commercially available tea made from coca (Erythroxylon coca) leaves. The Jockey Club in Great Britain commissioned research into this subject as several jockeys have tested positive for benzoylecognine over the past few years. Urine samples collected at various time points within 24 h after ingestion of a 250 ml infusion of Mate de Coca tea were analysed using three different methods. All samples tested positive for benzoylecognine.

Early acute rejection does not affect chronic allograft nephropathy and death censored graft failure

BACKGROUND

Even with the development of modern immunosuppression, an acute rejection episode is a major complication after renal transplantation. Acute rejection episodes have been used as clinical indicators for chronic allograft nephropathy and graft loss. We investigated the timing and frequency of acute rejection episodes in relation to long-term graft survival and chronic allograft nephropathy.

METHODS

The Long Term Efficacy and Safety Surveillance study of transplant patients receiving cyclosporin (Neoral) included 1706 adult renal transplants (1995 to 2003) with a functioning graft for at least 1 year. The impact on death-censored long-term graft survival was evaluated for acute rejection episodes (single or multiple) within 3 months, at 3 to 6 months, at 6 to 12 months, or at over 1 year posttransplant. A stepwise binary logistic regression was employed to identify independent risk factors for the time to occurrence of an acute rejection episode.

RESULTS

An acute rejection episode occurring within 3 months posttransplantation had no effect on either death-censored long-term graft failure (P=.2157) or chronic allograft nephropathy (P=.9331). However, an acute rejection episode occurring at 1 year or later posttransplantation was significantly associated with death censored long-term graft failure (P <.0001) and chronic allograft nephropathy (P <.0001). The numbers of HLA-DR mismatches and younger recipient ages were independent risk factors for early acute rejection.

CONCLUSION

Among patients whose graft survives at least 12 months, an early acute rejection episode within 3 months posttransplant was not associated with either death-censored long-term graft survival or chronic allograft nephropathy among adults treated with cyclosporin. However, an acute rejection episode occurring at 1 year or later posttransplantation showed a positive association with death-censored long-term graft survival or chronic allograft nephropathy. Lower numbers of HLA-DR mismatches sum to reduce the occurrence of acute rejection and the hospitalization time.

Fine needle aspiration cytology in the management of a parotid mass: a two centre retrospective study

OBJECTIVES

There is a diversity of opinion regarding the role of fine needle aspiration cytology (FNAC) in the pre-operative evaluation of the parotid mass. This study further investigates the role of FNAC from the standpoint of the clinician attempting to resolve one or more clinical issues.

METHODS

A retrospective study conducted at two UK Hospitals with no overlap of cytopathologists or surgeons. Patients undergoing parotidectomy at each institution were identified from Pathology department databases. The definitive histopathological diagnosis was compared with any pre-operative FNAC diagnosis. Cytology results were classified as suggestive, non-diagnostic, sampling error, or misleading.

SETTING

The study was conducted in a District General Hospital and a University Teaching Hospital providing secondary care for each community.

RESULTS

For the University Teaching Hospital the sensitivity in distinguishing malignant from benign disease was 79% (95% CI 61-97%) with a specificity 84% (95% CI 73-95%). However, three of eight patients with a primary parotid salivary gland malignancy were reported as having benign disease on FNAC. For the participating District General Hospital the sensitivity in distinguishing malignant from benign disease was 38% (95% CI 13-63%) and specificity 95% (95% CI 73-95%).

CONCLUSIONS

Fine needle aspiration cytology does not reliably distinguish a benign from a malignant primary salivary gland neoplasm in the participating institutions. Where clinical teams use FNAC in an attempt to resolve this clinical problem, the results should be interpreted with caution and an ongoing audit of performance is required.

A microparticle enzyme immunoassay to measure sirolimus

Measurement of sirolimus as a guide to therapy is widely accepted. Since the commercial introduction of the drug, the only method available to measure blood concentrations has been high-performance liquid chromatography (HPLC). Only a limited number of centers have the facilities to perform this technique and, as a result, the measurement of the drug has been performed in central laboratories, often some distance from the clinical centers. This article describes a single-center assessment of a new immunoassay to measure sirolimus, including a comparison between immunoassay results and a chromatographic technique. Calibration accuracy was good, reproducibility at 11 ng/mL was better than 6%, and sensitivity was better than 2 ng/mL; all these parameters are appropriate for routine clinical use. There was a mean positive bias of almost 20% for the measurement of sirolimus in clinical samples from kidney transplant patients receiving the drug, compared with HPLC. This bias was most likely due to cross-reactivity with metabolites of the drug and was of the order noted when an earlier configuration of this immunoassay was used in clinical practice. We conclude that, despite the analytical bias, this immunoassay offers a viable alternative to the use of HPLC and would be an assay suitable for implementing at local centers.

Therapeutic drug monitoring of cyclosporine

The introduction of cyclosporine into clinical practice improved transplant outcome. However, the use of cyclosporine is not without problems. A narrow therapeutic index (the drug causes irreversible kidney damage when given in too high a dose) coupled with variable absorption and unpredictable pharmacokinetics has resulted in the need to measure cyclosporine blood concentrations to enable the dose of the drug to be individualised to the patient. When this is done correctly therapeutic efficacy can be maximised while toxicity is kept to a minimum. The evolution of cyclosporine dose optimisation started with the adjustment of empirical fixed doses by clinical "judgement;" progressed to therapeutic drug monitoring of trough, predose, C0 concentration with non specific assays that measured parent drug and metabolite; then on to "specific" cyclosporine C0 measurements; through area under curve monitoring using full profile measurements and limited sampling scheme procedures; and finally ending up with absorption profiling that targets AUC in the first 4 hours or the 2 hour blood cyclosporine concentration, C2. At the same time the formulation of cyclosporine has changed from Sandimmune to Neoral and now generic forms of the latter are available. The evidence base supporting C2 monitoring continues to grow and the technique will need to be customised as new combination therapies emerge. Therapeutic drug monitoring of cyclosporine may also need to be tailored to avoid the potential negative impact of switching patients to generic forms of the drug.

A survey to determine the blood concentration of cyclosporine 2 hours postdose in stable renal transplant patients

The current method for monitoring cyclosporine measures predose concentrations (C0). A better method has been developed, namely, measurement of the blood cyclosporine concentration at 2 hours postdose (C2). The aim of this survey was to determine the variability of C0 and C2 concentrations among stable renal transplant patients. One hundred two stable renal transplant patients who were at least 6 months posttransplant were recruited from the renal transplant outpatient clinic. The cyclosporine dose was between 100 and 500 mg daily; all patients had been monitored using C0 concentrations. Blood samples for cyclosporine concentration measurements were taken at both C0 and C2 at two consecutive clinic visits. The within- and between-patient variabilities were calculated using nested analysis of variance. The mean age was 50 years (21 to 81); the mean weight was 75 kg. The mean cyclosporine dose was 3.18 mg/kg/d (1.2 to 8.8). The average serum creatinine was 174 micromol/L (77 to 626) and the average cholesterol was 5 micromol/L (3 to 9). The mean (+/-SD) C0 concentration was 150 (47.31) microg/L and C2=895 (239) microg/L. The C0 concentration varied over 16-fold between patients compared to a sevenfold variation in C2. The between-subject coefficient of variation (CV) was 35% for C0 and 30% for C2 and the within subject CV was 23% for C0 and 20% for C2. The results suggest that cyclosporine concentrations at C0 are slightly more variable than those at C2. Whether this modest reduction in variability results in better patient outcomes is the subject of the next phase of this study.

The relative proportions of sirolimus metabolites in blood using HPLC with mass-spectrometric detection

Measurement of sirolimus in blood as a guide to dose adjustment is an accepted practice. To date, most data have resulted from the use of a chromatographic technique. With the imminent introduction of an immunoassay into this field, there is a need to know whether metabolites that could interfere with the performance of this assay, causing a bias compared with measurements made by a chromatographic assay, vary over a period of time or with changes in concomitant immunosuppressive therapy. This preliminary study measured several sirolimus metabolites in blood samples from a variety of clinical settings, using high-performance liquid chromatography with tandem mass-spectrometric detection. Two metabolites known to cross-react in one immunoassay system, single hydroxylation products and 41-O-demethyl rapamycin, were found to constitute the bulk of the metabolic products. They were also found to form a remarkably stable proportion of all metabolites measured, both with respect to the time since transplantation and the concomitant use of cyclosporine or tacrolimus. It is concluded that the analytical bias due to cross-reactivity with metabolites, inherent in this immunoassay, should be consistent across a wide spectrum of patients receiving the drug.