[Carotid aneurysm as a differential diagnosis of a cervical tumor]

This article presents the case of a patient with a submandibular cervical tumor initially suspected to be a large lymph node or glomus tumor. However, the diagnostic workup prior to taking a biopsy sample revealed an extracranial aneurysm of the internal carotid artery. In order to prevent a permanent neurologic deficit arising from thromboembolism, the aneurysm was excluded by resection and arterial continuity was restored. Extracranial aneurysms of the internal carotid artery are rare, but serious differential diagnoses of cervical nodes. It is of paramount importance that this differential diagnosis be considered before initiating invasive diagnostics of these tumors.

Photoluminescence studies of a perceived white light emission from a monolithic InGaN/GaN quantum well structure

In this work we demonstrate by photoluminescence studies white light emission from a monolithic InGaN/GaN single quantum well structure grown by metal organic chemical vapour deposition. As-grown and thermally annealed samples at high temperature (1000 °C, 1100 °C and 1200 °C) and high pressure (1.1 GPa) were analysed by spectroscopic techniques, and the annealing effect on the photoluminescence is deeply explored. Under laser excitation of 3.8 eV at room temperature, the as-grown structure exhibits two main emission bands: a yellow band peaked at 2.14 eV and a blue band peaked at 2.8 eV resulting in white light perception. Interestingly, the stability of the white light is preserved after annealing at the lowest temperature (1000 °C), but suppressed for higher temperatures due to a deterioration of the blue quantum well emission. Moreover, the control of the yellow/blue bands intensity ratio, responsible for the white colour coordinate temperatures, could be achieved after annealing at 1000 °C. The room temperature white emission is studied as a function of incident power density, and the correlated colour temperature values are found to be in the warm white range: 3260–4000 K.

Postoperative vocal fold palsy in patients undergoing thyroid surgery with continuous or intermittent nerve monitoring

Background

Continuous monitoring of electromyographic (EMG) amplitudes of the vocal muscles detects impending injury of the recurrent laryngeal nerve (RLN) during thyroid operations earlier than intermittent EMG monitoring. This may alert the surgeon to stop a manoeuvre causing stretching or pressure on the RLN, with better recovery of nerve function.

Methods

Patients with intact preoperative RLN function who underwent thyroid surgery for benign disease between January 2011 and September 2014 under continuous intraoperative nerve monitoring (CIONM) or intermittent intraoperative nerve monitoring (IIONM) were included in this observational study conducted at a tertiary surgical centre. For CIONM, combined EMG events indicative of imminent nerve injury were defined as an EMG amplitude decrease of 50 per cent or more and a latency increase of 10 per cent relative to baseline values. The rates of early and permanent palsy for the two groups of patients were compared.

Results

There were 1526 patients, 788 of whom (1314 nerves at risk) underwent thyroid surgery using CIONM and 738 (965 nerves at risk) had IIONM. With the use of CIONM, 63 (82 per cent) of 77 combined events were reversible during the operation. No permanent vocal fold palsy occurred with CIONM, whereas four unilateral permanent vocal fold palsies (0·4 per cent) were diagnosed after IIONM (P = 0·019).

Conclusion

Operation with CIONM resulted in fewer permanent vocal fold palsies compared with IIONM after thyroid surgery in patients with benign disease.

Defect Trapping and Annealing for Transition Metal Implants in Group III Nitrides

The annealing of implantation induced lattice damage in AlN, GaN and InN was studied by means of the perturbed angular correlation (PAC) technique using the PAC probe 181Hf(181Ta). In all three lattices substantial fractions of the probe atoms occupied substitutional lattice sites after annealing. A detailed investigation of the changes observed during isochronal annealing indicates differences in the recovery process. In GaN the trapping of a unique defect, possibly a Nitrogen vacancy, in an intermediate temperature range was found.

Importance of Early Screening and Prophylactic Thyroidectomy in Asymptomatic Nonindex RET Germline Carriers

Genetic testing for RET germline mutations affords rapid identification of germline carriers, offering the prospect of cure before C-cell hyperplasia (CCH) has progressed to medullary thyroid carcinoma (MTC). Although nonindex RET mutation carriers have a better prognosis than do the index patients, it remains to be ascertained whether age represents a risk factor for MTC when screening patients. The current institutional study (October 1994 through June 1999) was set up to compare asymptomatic nonindex patients who were grouped by age: < 20 years and > or = 20 years. Inclusion criteria were confirmed RET mutations in the germline, with no MTC being more advanced than pT1pN1M0. Adult patients (> or = 20 years) had MTC significantly more often (84% vs. 43%), significantly larger tumors (5 mm vs. 3 mm), and significantly higher basal calcitonin levels preoperatively (78.0 vs. 9.7 pg/ml) than their pediatric/adolescent counterparts (< 20 years). There was a close correlation between pT1 MTC and an elevated basal serum calcitonin level (r = 0.67; Spearman's rho). All three patients with lymph node metastases from MTC had elevated basal calcitonin levels. The two groups did not differ in terms of multifocality of MTC (pT1b), lymph node involvement (pN1) or bilateral lymph node metastasis (pN1b), or preoperative stimulated and postoperative basal and stimulated serum calcitonin. Prophylactic thyroidectomy should not be postponed beyond the age of 20, and it should be performed before basal serum calcitonin has turned positive. Pathologic conversion of stimulated serum calcitonin obviously marks the time in carriers of RET germline mutations when surgery should be scheduled at the latest to be prophylactic.

GaN:Pr3+ nanostructures for red solid state light emission

Photoluminescence study of praseodymium implanted and annealed GaN films, quantum wells, nanowires and quantum dots.

Selective ion-induced intermixing and damage in low-dimensional GaN/AlN quantum structures

Ion-induced intermixing and damage is evaluated in GaN/AlN superlattices of quantum dots (QDs) and quantum wells (QWs) using 100 keV Ar(+) implantation at low temperature (15 K). Despite the similar damage build up at low fluences, a significant increase of the damage accumulation takes place for QDs at high fluences. Elemental depth profiles were fitted with a diffusion model, revealing the higher intermixing efficiency in QD superlattices, significantly higher than for QWs. The scaling of diffusion length with the local fluence and defect concentration is understood on the basis of cascade mixing and migration of defects in the cation sublattice. The selective intermixing/damage of QDs is explained by the promotion of lateral diffusion mechanisms that result in smooth interfaces, as well as by an enhanced diffusivity due to the characteristic strain distribution in QD superlattices.

Loss of Survivin influences liver regeneration and is associated with impaired Aurora B function

The chromosomal passenger complex (CPC) acts as a key regulator of mitosis, preventing asymmetric segregation of chromosomal material into daughter cells. The CPC is composed of three non-enzymatic components termed Survivin, the inner centromere protein (INCENP) and Borealin, and an enzymatic component, Aurora B kinase. Survivin is necessary for the appropriate separation of sister chromatids during mitosis and is involved in liver regeneration, but its role in regenerative processes is incompletely elucidated. Whether Survivin, which is classified as an inhibitor of apoptosis protein (IAP) based on domain composition, also has a role in apoptosis is controversial. The present study examined the in vivo effects of Survivin ablation in the liver and during liver regeneration after 70% hepatectomy in a hepatocyte-specific knockout mouse model. The absence of Survivin caused a reduction in the number of hepatocytes in the liver, together with an increase in cell volume, macronucleation and polyploidy, but no changes in apoptosis. During liver regeneration, mitosis of hepatocytes was associated with mislocalization of the members of the CPC, which were no longer detectable at the centromere despite an unchanged protein amount. Furthermore, the loss of survivin in regenerating hepatocytes was associated with reduced levels of phosphorylated Histone H3 at serine 28 and abolished phosphorylation of CENP-A and Hec1 at serine 55, which is a consequence of decreased Aurora B kinase activity. These data indicate that Survivin expression determines hepatocyte number during liver development and liver regeneration. Lack of Survivin causes mislocalization of the CPC members in combination with reduced Aurora B activity, leading to impaired phosphorylation of its centromeric target proteins and inappropriate cytokinesis.

[Endocrine surgery for neck paraganglioma: operation, radiation therapy or wait and scan?]

BACKGROUND

Head and neck paraganglioma (HNP) represent rare endocrine tumors. Therapy is decided on genetic findings, tumor characteristics (e.g. tumor size, localization and dignity), age of patient and symptoms. In terms of local control radiation therapy is as equally effective as surgery but surgical morbidity rates secondary to cranial nerve injuries remain high.

PATIENTS

Based on 6 patients with 11 solitary (4 patients) and multiple (2 patients) HNP (8 carotid body tumors, 1 vagal, 1 jugular and 1 jugulotympanic paraganglioma) the specific characteristics of the need for surgery as well as correct choice of treatment in cases of sporadic succinate dehydrogenase (SDH) negative and hereditary SDH positive HNP will be exemplarily demonstrated.

RESULTS

A total of 6 carotid body tumors (four sporadic, two hereditary) were resected in 4 patients, five as primary surgery and one as a revision procedure. In one case a preoperative embolization was performed 24 h before surgery. Malignancy could not be proven in any patient. The 30-day mortality was zero. In the patient with bilateral hereditary carotid body tumors, unilateral local recurrent disease occurred. After resection of the recurrent tumor permanent unilateral paralysis of the laryngeal nerve, glossopharyngeal nerve and hypoglossal nerve occurred. All patients were followed-up postoperatively for a mean of 64 months (range 23-78 months) with a local tumor control rate of 100%. The overall survival rate after 5 years was 100%.

CONCLUSIONS

Given a very strict indication with awareness of surgical risks selective surgery has a key position with low postoperative morbidity in the treatment of HNPs. We prefer surgery for small unilateral paraganglioma, malignant or functioning tumors.

Loss of the nerve monitoring signal during bilateral thyroid surgery

Background

This study aimed to assess current use of recurrent laryngeal nerve monitoring (RLNM) for bilateral thyroid surgery in Germany. It explored the willingness of surgeons to change strategy after loss of signal (LOS) on the first side of resection.

Methods

Surgical departments in Germany equipped with nerve monitors were asked to complete a structured questionnaire, specifying the number of thyroidectomies done in 2010, and the frequencies of RLNM, vagal stimulation, and electromyographic (EMG) recording before and after thyroidectomy. They were also asked about the surgical plan for bilateral goitre after LOS on the first side of resection.

Results

Based on manufacturers' sales data, 1119 (89·1 per cent) of 1256 surgical departments in Germany were equipped with nerve monitors in 2010. A total of 595 departments (53·2 per cent), accounting for approximately 75 per cent of all thyroidectomies in Germany during that year, returned a completed questionnaire. RLNM was used in 91·7–93·5 per cent of thyroidectomies, with the addition of routine vagal stimulation in 49·3 per cent before, and 73·8 per cent after resection. EMG responses to vagal stimulation were recorded in 54·8 per cent before, and 72·5 per cent after resection. Some 93·5 per cent of surgeons changed the resection plan for the other side in bilateral thyroid surgery after LOS had occurred on the first side.

Conclusion

RLNM is now the standard of care during thyroidectomy in Germany. After LOS on the first side of resection in bilateral goitre, more than 90 per cent of respondents declared their willingness to change the resection plan for the contralateral side to avoid the risk of bilateral recurrent laryngeal nerve palsy.