Personalized Medicine in Medullary Thyroid Carcinoma: A Broad Review of Emerging Treatments

Medullary thyroid carcinoma (MTC) arises from parafollicular cells in the thyroid gland, and although rare, it represents an aggressive type of thyroid cancer. MTC is recognized for its low mutational burden, with point mutations in RET or RAS genes being the most common oncogenic events. MTC can be resistant to cytotoxic chemotherapy, and multitarget kinase inhibitors (MKIs) have been considered a treatment option. They act by inhibiting the activities of specific tyrosine kinase receptors involved in tumor growth and angiogenesis. Several tyrosine kinase inhibitors are approved in the treatment of advanced MTC, including vandetanib and cabozantinib. However, due to the significant number of adverse events, debatable efficiency and resistance, there is a need for novel RET-specific TKIs. Newer RET-specific TKIs are expected to overcome previous limitations and improve patient outcomes. Herein, we aim to review MTC signaling pathways, the most recent options for treatment and the applications for personalized medicine.

Generation of an Obese Diabetic Mouse Model upon Conditional Atrx Disruption

Atrx loss was recently ascertained as insufficient to drive pancreatic neuroendocrine tumour (PanNET) formation in mice islets. We have identified a preponderant role of Atrx in the endocrine dysfunction in a Rip-Cre;Atrx^KO genetically engineered mouse model (GEMM). To validate the impact of a different Cre-driver line, we used similar methodologies and characterised the Pdx1-Cre;Atrx^KO (P.Atrx^KO) GEMM to search for PanNET formation and endocrine fitness disruption for a period of up to 24 months. Male and female mice presented different phenotypes. Compared to P.Atrx^WT, P.Atrx^HOM males were heavier during the entire study period, hyperglycaemic between 3 and 12 mo., and glucose intolerant only from 6 mo.; in contrast, P.Atrx^HOM females started exhibiting increased weight gains later (after 6 mo.), but diabetes or glucose intolerance was detected by 3 mo. Overall, all studied mice were overweight or obese from early ages, which challenged the histopathological evaluation of the pancreas and liver, especially after 12 mo. Noteworthily, losing Atrx predisposed mice to an increase in intrapancreatic fatty infiltration (FI), peripancreatic fat deposition, and macrovesicular steatosis. As expected, no animal developed PanNETs. An obese diabetic GEMM of disrupted Atrx is presented as potentially useful for metabolic studies and as a putative candidate for inserting additional tumourigenic genetic events.

Characterisation of an Atrx Conditional Knockout Mouse Model: Atrx Loss Causes Endocrine Dysfunction Rather Than Pancreatic Neuroendocrine Tumour

Simple Summary

ATRX and DAXX mutations occur in 30–40% of pancreatic neuroendocrine tumours (PanNETs), and there are no reports in the literature of any genetically engineered mouse model (GEMM) evaluating the effect of Atrx disruption as a putative driver event on PanNET initiation. We created a novel GEMM with Atrx conditional disruption in β cells. We observed that this genetic alteration, per se, was not tumourigenic, but we reported novel roles of Atrx on endocrine function, which resulted in dysglycaemia and the exacerbation of inflammageing (increased pancreatic inflammation and hepatic steatosis).

Abstract

ATRX is a chromatin remodeller that maintains telomere homeostasis. Loss of ATRX is described in approximately 10% of pancreatic neuroendocrine tumours (PanNETs) and associated with poorer prognostic features. Here, we present a genetically engineered mouse model (GEMM) addressing the role of Atrx loss (Atrx^KO) in pancreatic β cells, evaluating a large cohort of ageing mice (for up to 24 months (mo.)). Atrx loss did not cause PanNET formation but rather resulted in worsening of ageing-related pancreatic inflammation and endocrine dysfunction in the first year of life. Histopathological evaluation highlighted an exacerbated prevalence and intensity of pancreatic inflammation, ageing features, and hepatic steatosis in Atrx^KO mice. Homozygous floxed mice presented hyperglycaemia, increased weights, and glucose intolerance after 6 months, but alterations in insulinaemia were not detected. Floxed individuals presented an improper growth of their pancreatic endocrine fraction that may explain such an endocrine imbalance. A pilot study of BRACO-19 administration to Atrx^KO mice resulted in telomere instability, reinforcing the involvement of Atrx in the maintenance of β cell telomere homeostasis. Thereby, a non-obese dysglycaemic GEMM of disrupted Atrx is here presented as potentially useful for metabolic studies and putative candidate for inserting additional tumourigenic genetic events.

Workplace mistreatment and mental health in female surgeons in Pakistan

Background

Despite workplace mistreatment, which includes harassment, bullying and gender discrimination(GD)/bias, being serious problems for female surgeons, there are limited data from lower–middle-income countries like Pakistan. This study explored harassment and GD/bias experienced by female surgeons in Pakistan, and the effects of these experiences on mental health and well-being.

Methods

A nationwide survey was conducted between July and September 2019 in collaboration with the Association of Women Surgeons of Pakistan, an organization consisting of female surgeons and trainees in Pakistan. An anonymous online survey was emailed directly, disseminated via social media platforms (such as Facebook, Twitter and Instagram), and sent to surgical programmes in Pakistan.

Results

A total of 146 women surgeons responded to the survey; 67.1 per cent were trainees and the rest attending surgeons. Overall, 57.5 per cent of surgeons reported experiencing harassment, most common being verbal (64.0 per cent) and mental (45.9 per cent), but this mostly went unreported (91.5 per cent). On multivariable analysis adjusted for age and specialty, workplace harassment (odds ratio 2.02 (95 per cent c.i. 1.09 to 4.45)) and bullying (odds ratio 5.14 (95 per cent c.i. 2.00–13.17)) were significantly associated with severe self-perceived burnout, while having a support system was protective against feelings of depression (odds ratio 0.35 (95 per cent c.i. 0.16 to 0.74)). The overwhelming majority (91.3 per cent) believed that more institutional support groups were needed to help surgeons with stress reduction (78.8 per cent), receiving mentorship (74.7 per cent) and work–life balance (67.8 per cent).

Conclusion

Workplace mistreatment, in particular harassment and bullying, has a damaging impact on the mental well-being of female surgeons, particularly trainees. The absence of support groups in Pakistan should be urgently addressed so that surgeons, especially trainees, may cope better with potentially harmful workplace stressors.

Deep Brain Stimulation of the dorsal raphe abolishes serotonin 1A facilitation of AMPA receptor-mediated synaptic currents in the ventral hippocampus

In a previous study we showed that Deep Brain Stimulation (DBS) of the rat dorsal subregion of the dorsal raphe (DRD), which sends serotonergic projections to forebrain areas, such as the ventral hippocampus, induces anxiolytic-like effects. The purpose of the present study was to investigate neurobiological alterations which might underline these behavioral effects. For that, we tested the influence of DBS upon the neuromodulatory action of serotonin on excitatory post-synaptic currents (EPSCs) in the ventral hippocampus. Male Wistar rats were submitted to high-frequency stimulation (100 μA, 100 Hz) of the DRD for 1 h during three consecutive days. On the third day, immediately after the DBS procedure, animals were euthanized. Slices of the ventral hippocampus were processed for whole cell patch clamp recordings of AMPA-receptor (AMPAR) mediated EPSCs in the CA1 area. As reported by others, we confirmed that in pre-weaning rats a high affinity 5-HT1A receptor agonist (8-OH-PIPAT, 0.5-5nM) inhibits EPSCs. However, in adult rats (non-operated or sham-operated), 8-OH-PIPAT (0.5-5 nM) increased EPSC amplitude, an effect blocked by the 5-HT1A antagonist WAY-100,635 (200 nM). Importantly, in adult rats exposed to DBS, the 5-HT1A agonist was devoid of effect. Taken together these results show that: 1) changes in 5-HT1A receptor-mediated hippocampal synaptic transmission occur with age; 2) these changes lead to a facilitatory effect of 5-HT1A receptors; 3) DBS blocks this serotonergic facilitatory action. These observations suggest that an alteration in serotonin modulation of limbic areas may underlie the psychotherapeutic effects of DBS.

Clinical and epidemiological profile of women with breast cancer managed in a public referral hospital in northeastern Brazil

AIM

To evaluate the clinical and epidemiological profile of women with breast cancer, managed in the Breast Service at Hospital Get6lio Vargas (HGV).

MATERIALS AND METHODS

A descriptive, observational cross-sectional study, involving 174 breast cancer patients, managed at the Breast Service at HGV in Teresina, in the northeast of Brazil, from May 2011 to June 2014. Epidemiological variables included age group, age at menarche, age at first childbirth, and menopause. The tumor characteristics studied were histological type, TNM classification, and staging. The results were organized in distribution tables.

RESULTS

Breast carcinoma was more common in patients aged 60 and over, in multiparous women, and in women who were menopausal before age 55. The most common histological type was ductal invasive carcinoma T2N1MO (Stage IIB) in 83 (48%) women.

CONCLUSION

The current study shows that the majority of carcinomas were Stage II or advanced tumors, with clinically positive axillary lymph node status and weak correlation with reproductive risk factors.

A practical approach to the lateral cutaneous nerve of the thigh: an anatomical study

OBJECTIVES

To study the main anatomical landmarks related to the lateral cutaneous nerve of the thigh (LCN) in the infrainguinal region and to define reliable criteria for identifying the nerve during the surgery and electrophysiological study.

METHODS

Bilateral dissections of 60 adult non-fixed cadavers were performed with measurements of the distance between the inferior border of the anterior superior iliac spine (ASIS) and the LCN (DAL) and the internal angle between the LCN and the inguinal ligament (IA). The number of nerves exiting the inguinal ligament, the position of the LCN relative to the ASIS and to inguinal ligament were observed and registered. A triangle was designed using the inguinal ligament, the ASIS and the direction of tendinous insertions of the tensor of fascia lata muscle as parameters and the nerves were tested according its localization inside the triangle in each dissection.

RESULTS

In 80% of the dissections, the LCN passed under the inguinal ligament and was identified lateral to ASIS in only three dissections. A great variability was observed in the values of DAL and IA. The values of DAL ranged from 0 (immediately medial to ASIS) to 5 cm on either side with means of 1.31 and 1.22 cm on the right and left side, respectively. The values of IA ranged from 40° to 120°, with a mean of 66.08° on the right side and from 40° to 130° with a mean of 69.92° on the left side. No significant differences were identified between the two sides with respect to the relationship between the nerve and the inguinal ligament (Chi-square test, p=0.83); DAL (t test, p=0.37) or IA (t test, p=0.15). A single nerve was found in 70.83% of the dissections. The nerve was found inside the triangle in 95% of the dissections.

CONCLUSIONS

Despite the symmetry found between the right and left sides, the values of the main anatomic parameters involved in the localization of the LCN presented a great degree of variability. Even so, dissection using the proposed anatomical triangle allows for the localization of the LCN in almost all cases.

Effects of eliminating tension by means of epineural stitches: a comparative electrophysiological and histomorphometrical study using different suture techniques in an animal model

Epineural stitches are a means to avoid tension in a nerve suture. We evaluate this technique, relative to interposed grafts and simple neurorraphy, in a rat model. METHOD: Twenty rats were allocated to four groups. For Group 1, sectioning of the sciatic nerve was performed, a segment 4 mm long discarded, and epineural suture with distal anchoring stitches were placed resulting in slight tension neurorraphy. For Group 2, a simple neurorraphy was performed. For Group 3, a 4 mm long graft was employed and Group 4 served as control. Ninety days after, reoperation, latency of motor action potentials recording and axonal counts were performed. Inter-group comparison was done by means of ANOVA and the non-parametric Kruskal-Wallis test. RESULTS: The mean motor latency for the simple suture (2.27±0.77 ms) was lower than for the other two surgical groups, but lower than among controls (1.69±0.56 ms). Similar values were founding in both group 1 (2.66±0.71 ms) and group 3 (2.64±0.6 ms). When fibers diameters were compared a significant difference was identified between groups 2 and 3 (p=0.048). CONCLUSION: Good results can be obtained when suturing a nerve employ with epineural anchoring stitches. However, more studies are needed before extrapolating results to human nerve sutures.

Management of brachial plexus region tumours and tumour-like conditions: relevant diagnostic and surgical features in a consecutive series of eighteen patients

BACKGROUND

Tumours of the brachial plexus region are rare and most publications are case reports or studies with a small series of patients. The aim of this study is to present our experience in managing these lesions.

METHODS

We review 18 patients with tumours in the brachial plexus region submitted to surgical treatment in a 6 year period, including their clinical presentation, neuro-imaging data, surgical findings and outcome.

FINDINGS

The tumours comprised a heterogeneous group of lesions, including schwannomas, neurofibromas, malignant peripheral nerve sheath tumour (MPNST), sarcomas, metastases, desmoids and an aneurysmal bone cyst. The most common presentation was an expanding lump (83.33%). Eleven tumours were benign and 7 were malignant. Neurofibromatosis was present in only 2 patients (11.11%). Gross total resection was achieved in 14 patients and sub-total resection in the others. Only 3 patients presented with new post-operative motor deficits. The incidence of complications was low (16.5 %).

CONCLUSIONS

The majority of tumours were benign and most of them could be excised with a low incidence of additional deficits. Some of the malignant tumours could be controlled by surgery plus adjuvant therapy, but this category is still associated with high morbidity and mortality rates.

Magnetic resonance imaging of idiopathic carpal tunnel syndrome: correlation with clinical findings and electrophysiological investigation

OBJECTIVE

To compare clinical evaluation, electrophysiological investigation and magnetic resonance findings in assessing the severity of idiopathic carpal tunnel syndrome.

PATIENTS AND METHODS

Seventy-four patients with idiopathic carpal tunnel syndrome were prospectively recruited. Clinical evaluation included symptoms severity score and two-point discrimination, sensory and motor nerve conduction velocities were determined by electroneuromyography and imaging parameters were obtained after wrist magnetic resonance. The Wilcoxon test was used to define the differences between measurements of median nerve area. The Pearson and Spearman correlation tests were used to determine the relationships between all the measured parameters.

RESULTS

Cross-sectional area of median nerve was smaller at hamate level than at radio-ulnar joint and pisiform levels (p<0.001). With exception of median nerve area at hamate level, there was a lower degree of correlation between MRI parameters and findings obtained by clinical assessments and electrophysiological measurements. The median nerve area at hamate level correlated negatively with duration of symptoms, two-point discrimination, symptoms severity score and positively with sensory nerve conduction velocity (p<0.01).

CONCLUSION

In patients with idiopathic carpal tunnel syndrome, median nerve area measured by wrist magnetic resonance at hamate level may be considered as a valuable indicator to grading the severity of disease.

A case of isolated tuberculoid leprosy of antebrachial medial cutaneous nerve

Leprosy is an infectious disease of prevalence still high in endemic areas in Brazil. The neurological presentation depends on the involved nerve and is usually associated with skin lesions and the formation of multiple abscesses. We present a case of isolated tuberculoid leprosy, discuss the occurrence, the differential diagnosis and the treatment of this rare presentation and reaffirm the importance of considering leprosy in the differential diagnosis of patients with polyneuropathy or nerve enlargement with no skin lesions.

[Antistreptolysin O titer profile in acute rheumatic fever diagnosis]

OBJECTIVE: To determine ASO titer profile by establishing ARF differential diagnoses of other diseases with high levels of ASO antibodies. METHODS: We investigated 78 patients with ARF at onset and follow-up, 22 with isolated chorea at onset, 45 with recurrent oropharyngeal tonsillitis, and 23 with recent flare of juvenile idiopathic arthritis. We tested ASO with automated particle-enhanced immunonephelometric assay (Behring(R)-Germany). The ASO (IU/ml) titers were assessed at the following time intervals: 0-7 days, 1-2 weeks, 2-4 weeks, 1-2 months, 2-4 months, 4-6 months, 6-12 months, 1-2 years, 2-3 years, 3-4 years, and 4-5 years after onset of ARF. RESULTS: ASO titers in patients diagnosed with ARF had a significant increase up to the 2-4-month time interval (P<0.0001). Baseline levels were observed afterwards in patients under regular penicillin prophylaxis. The levels of ASO in ARF were also significantly higher than in patients with isolated chorea, recurrent oropharyngeal infections or juvenile idiopathic arthritis (P=0.0025), when age-matched samples of these groups were compared. The testacute;s sensitivity was 73.3% and the specificity was 57.6%, and it was calculated taking into account the upper limit of normality at 320 IU/ml, as well as the established diagnosis of ARF. The testacute;s specificity and positive predictive value increased with rising or higher titers, being higher with titers above 960 UI/ml. CONCLUSION: This reappraisal of ASO profile in ARF patients indicates a remarkable response during the acute phase, and that points to the extent to which ASO levels may differentiate ARF from other diseases with high levels of ASO antibodies, as coincidental but unrelated streptococcal infection or chronic arthritis flareup.

Surgical management of Guyon's canal syndrome, an ulnar nerve entrapment at the wrist: report of two cases

Guyon's canal syndrome, an ulnar nerve entrapment at the wrist, is a well-recognized entity. The most common causes that involve the ulnar nerve at the wrist are compression from a ganglion, occupational traumatic neuritis, a musculotendinous arch and disease of the ulnar artery. We describe two cases of Guyon's canal syndrome and discuss the anatomy, aetiology, clinical features, anatomical classification, diagnostic criteria and treatment. It is emphasized that the knowledge of both the surgical technique and anatomy is very important for a satisfactory surgical result.

Tumor cell-derived TGF-beta and IL-10 dysregulate paclitaxel-induced macrophage activation

Paclitaxel (TAXOL) activates in vitro macrophage (Mø) expression of proinflammatory and cytotoxic mediators, including IL-12, tumor necrosis factor alpha (TNF-alpha), and nitric oxide (NO). However, tumors dysregulate Mø through soluble suppressor molecules, and it is possible that tumors evade paclitaxel-mediated immune effector function through the production of immunomodulatory molecules and inhibition of Mø function in situ. Because Mø activation in the tumor microenviroment is a desirable goal of anti-tumor immunotherapy, we evaluated whether tumor-derived immunomodulatory factors dysregulate paclitaxel-mediated Mø activation. Tumor cell-derived supernatant suppressed paclitaxel's capacity to induce IL-12, TNF-alpha, and NO production by RAW264.7 Mø. Tumor factors also dysregulated paclitaxel-induced expression of a HIV-LTR, promoter-driven luciferase construct in RAW264.7 Mø, suggesting that tumors may inhibit a broad range of Mø functionality. Depletion studies revealed that IL-10 and transforming growth factor-beta1 (TGF-beta1), but not prostaglandin E2 (PGE2), impaired paclitaxel-mediated activation, suggesting that abrogation of these factors in situ might restore paclitaxel's activating capacity and enhance anti-tumor efficacy.

[Intraspinal dermoid tumor associated with diastematomyelia: case report]

Intraspinal dermoid tumor and diastematomyelia is a rare combination of pathologies and only eight cases were priorly published. We report a new case in an adult with clinical presentation of progressive paresis and sensitive deficit in the lower limbs, associated with a thoraco-lombar kyphoscoliosis. The diagnosis based on the CT scan and MR images was confirmed at surgery. Pathophysiologic and clinical aspects as well as the radiological characteristics of these pathologies are dicussed and the importance of the early diagnosis is emphasized.

[Lupus glomerulonephritis: a long-term follow-up]

PURPOSE

To evaluate and the long term course of patients with lupus nephritis,

METHOD

Thirty seven patients with lupus nephritis followed in a referral, tertiary care center of a developing country (Brazil) were studied. The length of follow up was 52.4 + 13.3 months and mean age was 26.05 + 11.12 years. 84% of the patients were females and class IV nephritis was found to be the most frequent (80%).

RESULTS

At the time of renal biopsy mean serum creatinine was 1.74 + 1.15 mg/dl, and 24 h-proteinuria was 2.62 + 2.89 g. Fifty one per cent of the patients with elevated serum creatinine showed a decrease in these values. Of the variables studied (age, sex, proteinuria, presence of hypertension and serum creatinine at biopsy), serum creatinine elevation was the only one to be associated with poorer prognosis. Remission of the nephrotic syndrome occurred in 65% of the patients. Actuarial survival rate was 96% at 1 year, 82% at 5 years, 70% at 10 years and 70% at 12 years. Five patients developed end stage renal failure and 7 died. Infection was the most frequent(57%) cause of death.

CONCLUSION

Among several factors studied the only which has been associated with chronic renal failure was elevated serum creatinine at the time of biopsy. Infections were the main cause of death.

Spontaneous epidural hematoma following a shunt in an infant with congenital factor X deficiency. Case report and literature review

The authors describe a case of an infant with congenital factor X deficiency. The patient presented with a central nervous system hemorrhage followed by hydrocephalus. He underwent a ventriculoperitoneal shunt and, during the postoperative period, developed a spontaneous epidural hematoma, which was evacuated. The clinical and pathophysiological aspects of this case are discussed based on a literature review.

[Acoustic neuroma in children without association with neurofibromatosis. Report of 2 cases]

Acoustic schwannoma is the most common tumor of the cerebellopontine angle in adults and is rarely found in children without neurofibromatosis. In the literature there are 18 children under the age of 16 with such tumor. Two female patients with age of 9 and 15 years old with acoustic schwannoma without neurofibromatosis are related. Progressive deafness followed by signs and symptoms of a posterior fossa tumor were the initial complaint of both, as well as of the other related cases and in adulthood.

[Intraneural synovial cyst of the peroneal nerve. Case report]

The authors report the case of an intraneural synovial cyst of the peroneal nerve. The initial symptom was pain and weakness of dorsiflexion and eversion of the right foot. The patient was operated on and the cyst was totally resected. The authors discuss the pathogenesis, clinical diagnosis as well as the treatment of that uncommon lesion.

[Lipoma of the corpus callosum with extracranial extension through frontal bone defect]

Intracranial lipoma are usually localized in the corpus callosum and rarely extends to the subgaleal region. Only eight cases of lipoma of the corpus callosum with extracranial extension were reported in the literature. Seizures and mental retardation were the most common clinical findings in these patients. Data from the literature show that resection of intracranial lipoma has catastrophic results. The resection must be restricted to the extracranial portion. We report a child with lipoma of the corpus callosum with extracranial extension with no neurologic deficit submitted to resection of the extracranial extension.