Effects of methylene blue on propofol requirement during anaesthesia induction and surgery

Intraoperative Adjunct Methods for Localization in Primary Hyperparathyroidism

Primary hyperparathyroidism (pHPT) is a frequently seen endocrine disease, and its main treatment is surgery. In the majority of pHPT, the disease involves only a single gland, and the majority of the pathological glands can be determined by preoperative localization methods.In addition to preoperative localization studies in parathyroidectomy, the use of adjunct methods to improve intraoperative localization in order to increase success of surgery is becoming widespread. These methods include different approaches, mainly intraoperative parathyroid hormone (PTH) measurement, followed by intraoperative gamma probe application, intraoperative ultrasonography, parathyroid imaging with methylene blue, and frozen section examination. Recently, especially promising new imaging methods have been described in the literature with various optical technologies to increase the localization of the parathyroid glands and to evaluate their viability. These methods include parathyroid imaging with autofluorescence, indocyanine green imaging with autofluorescence, autofluorescence imaging with methylene blue, autofluorescence imaging with 5-aminolevulinic acid, optical coherence tomography, laser speckle contrast imaging, dynamic optical contrast imaging, and Raman spectroscopy. Currently, minimally invasive parathyroidectomy has become the standard treatment for selected pHPT patients with the aid of preoperative imaging and intraoperative auxiliary methods . The aim of the present study was to evaluate the routinely used new promising intraoperative adjunct methods in pHPT.

Nitric Oxide and Related Aspects Underlying Angina

Increased number of patients affected by metabolic syndrome (MS) has prompted the necessity of better understanding what is involved in such syndrome. Nevertheless, the establishment of promising therapies depends on the knowledge about the interaction of molecules within MS. In such context, Nitric Oxide (NO) emerges from a bulk of works relating its roles on aspects of MS, including cardiovascular diseases, their symptoms and comorbidities, which are thought to be triggered by similar sources. NO, nitric oxide synthase and enzymatic chains are keys for those disease and symptoms processes. NO has been separately described as part of hypertensive, ischemic and pain signaling. Although there are similar pathways likely shared for generating cardiovascular symptoms such angina, they are barely associated to NO in literature. The present review aims to clarify the patterns of NO alteration in metabolic syndrome directly concerned to cardiovascular symptoms, especially angina.

Video assisted thoracoscopic excision of mediastinal ectopic parathyroid adenomas: a UK regional experience

BACKGROUND

To report the first series of video-assisted thoracoscopic surgery (VATS) resection of mediastinal ectopic parathyroid adenomas (MEPAs) in the UK.

METHODS

A case series of seven cases undergoing VATS between 2004 and 2009 to treat single gland hyperparathyroidism. Methylene blue (MB) was used in 5/7 cases immediately before exploration to identify the adenomas. Carbon dioxide (CO2) up to pressures of 10 mmHg was used safely to deflate the lung in two cases.

RESULTS

There were five women and two men with a mean age of 53 years (range, 27-72 years). Histopathology confirmed successful resection of the parathyroid adenoma in 6/7 cases. There was one conversion to open thoracotomy due to bleeding from the azygos vein resulting from excessive traction. Despite marked MB uptake, this patient proved to have tuberculoid adenopathy and no parathyroid tissue was identified. Postoperative plasma calcium returned to normal in 6/7 patients and parathyroid hormone (PTH) level in 6/7 patients. The median hospital stay was 2 days and there was no mortality in this series.

CONCLUSIONS

MEPAs can be safely resected using VATS with minimal surgical morbidity, short drainage time and short hospital stay. CO2 insufflation and the intraoperative use of MB are safe and help to accurately localise the ectopic adenoma. VATS should be considered as the first-line approach for resection of MEPAs.

Evaluation of the protein biomarkers and the analgesic response to systemic methylene blue in patients with refractory neuropathic pain: a double-blind, controlled study

Aim

This study was carried out in patients with neuropathic pain in order to assess the analgesic effects and changes in protein biomarkers after the administration of methylene blue (MB), a diaminophenothiazine with antioxidant and anti-inflammatory properties, and with inhibitory effects on nitric oxide.

Materials and methods

Ten patients with chronic refractory neuropathic pain were randomized to receive either MB (10 mg/mL Methylthioninium chloride) 2 mg/kg (MB group) or MB 0.02 mg/kg (control group) infused over 60 minutes. Sensory function and pain (Numerical Rating Scale) were evaluated at baseline and at 60 minutes after the start of the infusion. The patients kept a pain diary during the next 24 hours and for the following 4 days. Plasma and urinary concentrations of 8-isoprostane-prostaglandin F2α (8-iso-PGF2α) and plasma protein biomarkers prior to and after the infusions were measured with radioimmunoassay and with proximity extension assay.

Results

A decrease of the Numerical Rating Scale at 60 minutes in comparison with baseline was observed in the MB (P=0.047) group. The decrease was significant between the MB and the control group on the day of and day after MB infusion (P=0.04 and P=0.008, respectively). There was no difference in systemic protein expressions between groups except for prolactin (PRL) (P=0.02). Three patients demonstrated diminished dynamic mechanical allodynia.

Conclusion

MB decreased the pain levels in patients with chronic therapy-resistant neuropathic pain on the first 2 days after administration. Known as an endocrine modulator on the anterior pituitary gland, MB infusion produced a decrease of PRL. The detailed role of PRL effects in chronic neuropathic pain remains undetermined.

Cellular and molecular actions of Methylene Blue in the nervous system

Methylene Blue (MB), following its introduction to biology in the 19th century by Ehrlich, has found uses in various areas of medicine and biology. At present, MB is the first line of treatment in methemoglobinemias, is used frequently in the treatment of ifosfamide-induced encephalopathy, and is routinely employed as a diagnostic tool in surgical procedures. Furthermore, recent studies suggest that MB has beneficial effects in Alzheimer's disease and memory improvement. Although the modulation of the cGMP pathway is considered the most significant effect of MB, mediating its pharmacological actions, recent studies indicate that it has multiple cellular and molecular targets. In the majority of cases, biological effects and clinical applications of MB are dictated by its unique physicochemical properties including its planar structure, redox chemistry, ionic charges, and light spectrum characteristics. In this review article, these physicochemical features and the actions of MB on multiple cellular and molecular targets are discussed with regard to their relevance to the nervous system.

Intraoperative adjuncts in surgery for primary hyperparathyroidism

PURPOSE

This paper is a review of the evidence base to produce recommendations for the use of intraoperative parathyroid hormone (PTH), radioguided parathyroidectomy (RGP), methylene blue (MB), frozen section, and intraoperative neuromonitoring during surgery for primary hyperparathyroidism (PHPT).

MATERIALS AND METHODS

A Medline keyword search of English-language articles led to the production of a draft document, subsequently revised by committee, containing levels of evidence and the grading of recommendations as proposed by the Agency for Healthcare Research and Quality.

RESULTS

Literature review provides the basis for clear recommendations on the use of intraoperative PTH at surgery for PHPT. There is little evidence to support the use of RGP, MB, routine frozen section, and intraoperative neuromonitoring.

Use of methylene blue in pheochromocytoma resection: case report

We report the use of intravenous Methylene blue to treat the hypotension occurring following adrenal vein ligation in a case of pheochromocytoma resection in a child. The potential benefits and problems, including correct dosage, are discussed.