Management of medullary carcinoma of the thyroid: a review

Medullary thyroid carcinoma (MTC) is an uncommon malignancy of neuroendocrine origin derived from the parafollicular C cells. Although infrequent, the interest in this cancer exceeds its incidence owing to its distinctive features and its characteristic association with other endocrine tumors. Although the majority of MTCs are sporadic, hereditary varieties occur in isolation or as a part of multiple endocrine neoplasia type 2 syndrome (MEN 2). Currently, complete surgical resection of the tumor and nodal metastases with a curative intent remains the mainstay of therapy. The role of adjuvant therapy is limited, although radiotherapy and newer targeted therapies are routinely used for metastatic disease. The lack of consensus in the available guidance regarding the most appropriate diagnostic, therapeutic and follow-up strategies has caused substantial variability in clinical practice. Therefore, this review summarizes the latest available evidence and guidelines on the management of MTC with an emphasis on diagnosis, surgical treatment and follow-up.     

Fast-track cardiac anaesthesia in the elderly: effect of two different anaesthetic techniques on mental recovery

Elderly patients may be considered for ‘fast-track’cardiac anaesthesia, but can suffer psychological complicationsand slow recovery of mental function after surgery, which caninterfere with recovery. Reduced metabolism and changed distributionof anaesthetic and sedative agents can cause poor recovery.We made a prospective randomized comparison of mental function,haemodynamic stability and extubation and discharge times inelderly patients (65–79 yr) receiving two premedication,anaesthetic and sedative techniques. Patients received eitherpropofol (n=39) (fentanyl 10–15 µg kg^–1and propofol 2–6 mg kg^–1 intraoperativelyand a propofol infusion for 3 h postoperatively) or premedicationwith lorazepam followed by midazolam for anaesthesia (n=39)(fentanyl 10–15 µg kg^–1 and midazolam0.05–0.075 mg kg^–1 intraoperatively anda midazolam infusion for 3 h postoperatively). Impairmentof mental function was noted in 41% of patients in the propofolgroup and 83% in the lorazepam and midazolam group (P=0.001)18 h after extubation. Patients in the propofol group wereextubated earlier [1.4 (SD 0.6) vs 1.9 (0.8) h, P=0.02];and reached standard intensive care unit discharge criteria[7.6 (4.6) vs 14.2 (13) h, P=0.02] and hospital dischargecriteria [4.3 (1.0) vs 4.9 (1.1) days, P=0.04) sooner than patientsin the lorazepam and midazolam group, but actual discharge timesdid not differ between the groups. Haemodynamic values werestable in both groups.Br J Anesth 2001; 86: 68–76     

Serum insulin patterns and the relationship between insulin sensitivity and glycaemic profile in women with polycystic ovary syndrome

Objective  To evaluate serum insulin levels and insulin sensitivity in women with polycystic ovary syndrome (PCOS) in relation to their glycaemic status.
Design  An observational study.
Setting  A tertiary-level reproductive health centre in Sri Lanka.
Sample  Infertile women diagnosed as having PCOS ( n  = 168) on the basis of the Rotterdam criteria were included in the study.
Methods  Glycaemic status and serum insulin values were assessed at fasting and at 2 hours after a 75-g oral glucose load and stratified as diabetes mellitus (DM) (10.12%), impaired glucose tolerance (IGT) (23.21%) and normoglycaemia (66.67%). The normoglycaemic group was restratified as groups A (10.7%), B (79.5%) and C (9.8%) on the basis of serum insulin levels, with group A having the lowest and group C the highest values. The Quantitative Insulin Sensitivity Check Index (QUICKI) scores of women with DM and IGT and those in groups A, B and C in the normoglycaemic category were compared.
Main outcome measures  Insulin sensitivity in these groups of women.
Results  Body mass index (BMI) exceeded 23 kg/m² in 77.38% of the women. In normoglycaemic women with PCOS, insulin sensitivity was highest in group A. In groups B and C, insulin sensitivities corresponded to those found for women with IGT and DM respectively. This pattern was also reflected in the BMI.
Conclusions  Normoglycaemic women with PCOS are heterogeneous regarding insulin sensitivity. The treatment offered to those with DM and IGT could be extended to subgroups B and C of normoglycaemic subjects. Normoglycaemic women with PCOS with high insulin sensitivity (group A) would not qualify for this treatment.     

Persistent inhibition of Candida albicans biofilm and hyphae growth on titanium by graphene nanocoating

ObjectivesCandida albicanscolonizes biomaterial surfaces and are highly resistant to therapeutics. Graphene nanocoating on titanium compromises initial biofilm formation. However, its sustained antibiofilm potential is unknown. The objective of this study was to investigate the potential of graphene nanocoating to decrease long-term fungal biofilm development and hyphae growth on titanium.MethodsGraphene nanocoating was deposited twice (TiGD) or five times (TiGV) on grade 4 titanium with vacuum assisted technique and characterized with Raman spectroscopy and atomic force microscope. The biofilm formation and hyphae growth of C. albicans was monitored for seven days by CFU, XTT, confocal, mean cell density and scanning electronic microscopy (SEM). Uncoated titanium was the Control. All tests had three independent biological samples and were performed in independent triplicates. Data was analyzed with one- or two-way ANOVA and Tukey's HSD (α = 0.05).ResultsBoth TiGD and TiGV presented less biofilms at all times points compared with Control. The confocal and SEM images revealed few adhered cells on graphene coated samples, absence of hyphae and no features of a mature biofilm architecture. The increase in number of layers of graphene nanocoating did not improve its antibiofilm potential.SignificanceThe graphene nanocoating exerted a long-term persistent inhibitory effect on the biofilm formation on titanium. The fewer cells that were able to attach on graphene coated titanium were scattered and unable to form a mature biofilm with hyphae elements. The findings open opportunities to prevent microbial attachment and proliferation on implantable materials without the use of antibiotics.     

Brain white matter hyperintensities in migraine: Clinical and radiological correlates

Objective

Migraine is a recognised cause of brain white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI). However radiological characteristics of those in migraine are not well defined. We sought to study the radiological characteristics and factors associated with WMH in migraine.

Methods

Migraine patients who were investigated with MRI of the brain in the outpatient clinic were studied retrospectively. Two groups were delineated based on the presence or absence of WMH in MRI scans. The clinical and demographic characteristics between the two groups were compared to delineate the associations of WMH.

Results

Forty four patients were studied, out of which 19 demonstrated WMH on MRI. Frontal lobe was involved in all subjects with WMH. Infratentorial hyperintensities were not seen in any. Subcortical and deep white matter was the commonest distribution while callosal and subcallosal lesions were very rare. Family history of migraine, increasing age, and increasing headache frequency emerged as significant associations of WMH in multivariable analysis.

Conclusions

There are characteristic radiological features and clinical associations of WMH in migraine.     

The energy response of a T.P.A. Mk-II ionization chamber using GEANT4 Monte Carlo simulation

The low energy model of the GEANT4 Monte Carlo toolkit was used to simulate the energy response of a T.P.A. Mk-II ionization chamber under a variety of different conditions. The sample position resulting in the maximum response along the axial direction of the chamber was obtained. The parameters of the simulation were chosen to account for the maximum effect of the particle backscattering and the setting of most suitable values for the production thresholds and the energy cuts in the GEANT4 Monte Carlo code. The chamber response for different compositions of detector elements was also studied. The simulated radioactive source was a glass ampoule containing 3.6 ml of the radionuclide in an aqueous solution. The energy response of the chamber at the maximum response was obtained for simulations for (60)Co, (22)Na and (59)Fe nuclides. Verification of the simulated response was obtained using experimental measurements with radioactive sources. The simulated results were in good agreement with the experimentally measured data to within 0.04-2.0%. In the energy range below 200 keV the response curve was complex due to the increase of photoelectric cross sections of the chamber materials. Effects due to backscattering occur at boundaries between chamber elements and also become significant at sites of lead shielding at photon energies above 700 keV. The chamber response for different compositions of detector elements was also studied. The response of the chamber depended highly on the energies of emitting particles, source position and materials used in electrodes and thimble wall.