In this review are discussed experimental and clinical data about the role of gut microbiota and its changes after bariatric surgery. To date, bariatric surgery represents the only treatment that enables substantial and sustained weight loss.

The large intestinal microbiota plays an important role in normal bowel function and the maintenance of host health through the formation of short chain fatty acids, modulation of immune system reactivity, and development of colonization resistance. The intestinal microflora is a peculiar indicator of the condition of a microorganism reacting to age, physiological, dietary, and geographical factors from change of qualitative and quantitative structure. Studies have demonstrated that obesity and metabolic syndrome may be associated with profound microbiotal changes. This Review outlines the potential mechanisms by which the major changes in the digestive tract after bariatric surgery can affect the gut microbiota.

Background: The high incidence of cervical lymph nodes metastasis in highly differentiated thyroid carcinoma (DTC) and insufficient of existing diagnostic methods determines the urgency of finding reliable and more effective tests.

Aims: The aim of our study is to determine the prognostic significance of the thyroglobulin measurement in washout fluid from fine-needle aspiration biopsy (FNA-Tg) and the cut-off value in the diagnosis of DTC lymph nodes metastasis.

Materials and methods: 245 patients evaluated for suspicious cervical lymph nodes were retrospectively reviewed. All patients underwent FNA-Tg, serum thyroglobulin (sTg) levels, thyroglobulin antibodies (Tg-Ab), thyroid-stimulating hormone (TSH) were measured. 125 patients with malignant changes according to FNA and/or high FNA-Tgvalues underwent surgical treatment. Patients were divided into 2 groups with reactive (n = 23) and metastatic (n = 102) changes. FNA-TG was assayed on automated system Cobas 601 (Roche, France).

Results: All patients were comparable by sex, age and levels of TSH, sTG, Tg-Ab. The FNA-Tg median in metastatic group was 537.0 [0.1; 1000], and in benign group – 17.9 [0.5; 158.0], p = 0.003. The sensitivity of isolated FNA was 85%, specificity 57%, AUC = 0.618, 95% CI 0.516–0.713. The sensitivity and specificity of FNA-Tg was 73% and 100%, respectively, AUC = 0.865, 95% CI 0.78–0.92. The optimal cut-off point for malignancy was >9.2 ng/ml (sensitivity 75%, specificity 100%), Youden Index 0.73.

Conclusions: Additional FNA-Tg may increase the sensitivity of isolated FNA in evaluation of DTC lymph node metastasis. The optimized cut-off value >9.2 ng/ml can be proposed as a diagnostic threshold for the definition of malignancy.

Background: In the preoperative diagnosis of thyroid tumors the cytological examination of the material of fine needle aspiration biopsy is the gold standard and serves as the basis for planning of treatment strategy. However, in 10–30% of cases, it cannot be clearly established by cytology whether the nature of thyroid neoplasm benign or malignant, which leads to the inability to choose the optimal treatment strategy in advance. For such cases, it is extremely important to search for methods of clarifying differential diagnosis, among which mutation testing is currently considered the most promising.

Aims: To evaluate the possibility of using mutation tests for clarifying differential diagnosis of thyroid neoplasms at the preoperative stage.

Materials and methods: We performed the prospective single center study, which included patients with the thyroid neoplasms, who had been treated in the Endocrinology Research Center, Moscow, Russia from 2012 to 2014. Samples of histological material, cytological material and blood plasma of these patients were tested for the presence of somatic mutations in hot spots of the genes BRAF, KRAS, NRAS, TERT, and EIF1AX.

Results: The study included 75 patients, 29 of them with low-risk papillary thyroid cancer, 29 with follicular neoplasm NA of the thyroid gland and 17 with colloid nodular goiter. Mutations in the “hot spots” of the BRAF gene (exon 15, codon area 600–601) were found in 29 patients, mutations in the “hot spots” of the NRAS gene (exon 3, codon 61) – in 8 patients; mutations in the hot spots of the KRAS, TERT and EIF1AX genes were not detected. Correlation of the results of mutational testing of cytological and histological material was 91.7%. Mutations of tumor origin in circulating blood plasma DNA were found in only 1 cases. The prognostic value of the positive result (PPV) of the mutation test on cytological material in relation to the malignant nature of the thyroid tumor was 100% for the BRAF gene and 0% for the NRAS gene.

Conclusions: The mutation test in the “hot spots” of the BRAF gene on cytological material can be used as an additional marker to clarify the nature of thyroid tumors, when the result of cytological examination are uncertain. Either in similar situations for mutation tests in the “hot spots” of genes KRAS, NRAS, EIF1AX and TERT on cytological material, or mutation testing of circulating DNA of blood plasma can’t be used as an additional marker.

Background: Disorders of water and electrolyte balance, hyper- and hyponatremia, are common postoperative complications of transsphenoidal neurosurgical interventions and are found in up to 30–40% of cases. At the same time, delayed hyponatremia is the main cause of repeated hospitalizations of patients, and the risk factors/pathogenetic mechanisms responsible for the development of postoperative hyponatremia have not been fully investigated.

Aim: To determine the frequency of water-electrolyte disturbances and to identify predictors of dysnatriemia states in patients after transnasal adenomectomy.

Materials and methods: A retrospective single-site study included an analysis of electronic medical records of patients who underwent transnasal neurosurgical interventions for benign tumors of the pituitary gland (n = 416). The diagnostic and prognostic factors for the development of postoperative water-electrolyte disorders were evaluated.

Results: The prevalence of hyponatremia in the total group of patients was 7.2%, and for hypernatremia it was 3 times higher – 24.3%, with these indicators being kept stable through the years of surgery (p > 0.05; χ² with the Yeats correction). 66 (16%) of the operated patients, the sodium level in the early (0–5 day) and 157 (38%) patients in the later (6+ day) postoperative period was not determined, which may underestimate the identification of the most dangerous delayed postoperative hyponatremia. When analyzing the main clinical and laboratory characteristics of patients with hypo-, normo- and hypernatremia, no statistically significant differences were found between the parameters characterizing natremia, the osmolality of blood and urine, the frequency of determining blood sodium in different time intervals of the postoperative period. Complications of the main diagnosis (diabetes mellitus, coronary heart disease and arterial hypertension), selected parameters of pathological examination (identification of neurohypophysis cells, adenohypophysis, oxyphilic, basophilic or chromophobic cells, as well as other structures that are not part of the pituitary gland) and the operation protocol (bleeding, coagulation of sellar structures, liquorrhea, excision of the pituitary gland), did not differ between groups. In the hypernatremia group, the tumor volume in quantitative representation was lower than in the normo- and hyponatremia groups (1.0 ml vs. 1.5 and 1.5 ml, respectively). The number of neurosurgical interventions performed in a patient did not differ between the study groups.

Conclusions: After transnasal adenomectomy, hypo- and hypernatremia occur in 7.2% and 24.3%, respectively, and do not depend on the presence of complications of the underlying disease, the parameters of the pathomorphological protocol, the appearance of postoperative hypopituitarism or the course of the operation itself. For the timely detection of disorders of water and electrolyte metabolism, the implementation of blood sodium testing in the early and late (6+ day) postoperative period is necessary in management of patients after transnasal adenomectomy.

A corrigendum on «Medullary thyroid cancer. Returning to the need to determine the preoperative basal calcitonin level in patients with thyroid nodular pathology»

by Elena E. Stanyakina, Ilia S. Romanov, Tatiana T. Kondratieva, Alexander S. Krylov, Alexey D. Ryzhkov, Sergey V. Shiryaev (2018). Endocrine Surgery. 12(4). doi: 10.14341/serg10044

There is an error on the page 189: "Blood test for hormones: thyroid stimulating hormone (TSH) — 52.6 mIU/l (reference values 0.25–4.0), adrenocorticotropic hormone (ACTH) <20 IU/ml (0–30), thyreoglobulin (TG) <0.2 ng/ml (0–30)". Instead of "antibodies to thyroglobulin (ATTG)" was published "adrenocorticotropic hormone (ACTH)".

The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way.

The original article has been updated.