Coexistence of DIPNECH and carotid body paraganglioma: is it just a coincidence?

SUMMARY

We describe the case of a 56 year-old woman with the almost simultaneous appearance of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) and a carotid body paraganglioma. Of interest, 6 years earlier, the patient underwent total thyroidectomy due to papillary thyroid carcinoma and, in the meantime, she was submitted to mastectomy to treat an invasive ductal carcinoma of the breast. In order to explain these lesions, an extensive genetic study was performed. Results showed positivity for the presence of the tumor suppressor gene PALB2, whose presence had already been detected in a niece with breast cancer. The patient underwent different procedures to treat the lesions and currently she is symptom-free over 2 years of follow-up.

LEARNING POINTS

The presence of two rare neoplasms in a single person should raise the suspicion of a common etiology. To the best of our knowledge, this is the first case that shows the coexistence of DIPNECH and paraganglioma. The contribution of the PALB2 gene in the etiology of these rare neoplasms is a possibility.

Thalidomide reduces mechanical hyperalgesia and depressive-like behavior induced by peripheral nerve crush in mice

BACKGROUND

It has been shown that chronic pain is able to induce depressive disorders in humans, in part, due to peripheral inflammation that reaches the central nervous system. However, the mechanisms involved remain to be established. The purpose of this study was to investigate whether sciatic nerve crush could produce depression-like behaviors, in addition to pain-related behaviors, in mice. Once confirmed, this model was used to investigate tumor necrosis factor-α (TNF-α) as a key mediator involved in the pathophysiology of both pain and depression.

EXPERIMENTAL APPROACH

Male Swiss mice were divided into three groups, naïve, sham and operated. In the operated group, the sciatic nerve was crushed. Following surgery, animals from the operated group were treated daily by oral gavage (p.o.) with saline (10 ml/kg), fluoxetine (20 mg/kg) or thalidomide (10 mg/kg) for 15 days. Mechanical hyperalgesia was evaluated every 3 days by von Frey filaments and depressive-like behavior was assessed at the end of day 15, using the tail suspension test (TST) and the forced swimming test (FST). Then, samples from the prefrontal cortex, hippocampus and sciatic nerve were processed to measure TNF-α levels by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Crush caused significant mechanical hyperalgesia and depressive-like behaviors and increased TNF-α levels in the sciatic nerve, prefrontal cortex and hippocampus of operated animals. Treatment with fluoxetine or thalidomide reversed crush-induced mechanical hyperalgesia, depressive-like behaviors and the increased TNF-α levels in the sciatic nerve, prefrontal cortex and hippocampus.

CONCLUSIONS

The sciatic nerve crush model represents a good model to study to mechanisms underlying both pain and depressive-like behaviors. Furthermore, inhibitors of TNF-α synthesis, like thalidomide, have a potential to treat depressive disorders associated with neuropathic pain.

Effects of Swimming on the Inflammatory and Redox Response in a Model of Allergic Asthma

In this study we hypothesized that swimming during sensitization phase could result in a preventive effect in mice with allergic asthma. Swiss mice were divided into 4 groups: Control and Swimming (non-sensitized), OVA and OVA+Swimming (sensitized). The allergic inflammation was induced by 2 intraperitoneal injections and 4 aerosol challenges using ovalbumin. Swimming sessions were performed at high intensity over 3 weeks. 48 h after the last challenge mice were euthanized. Swimming decreased OVA-increased total IgE, IL-1, IL-4, IL-5 and IL-6 levels, as well as the number of total cells, lymphocytes and eosinophils in bronchoalveolar lavage fluid, (p<0.05). Simultaneously, swimming also increased IL-10 and glutathione levels in the Swimming and OVA+Swimming groups (p<0.05). The levels of glutathione peroxidase and catalase were increased only in the Swimming group when compared to all groups (p<0.05). 21 days of swimming resulted in an attenuation of pulmonary allergic inflammation followed by an increase of glutathione levels in the OVA group. Swimming only increased the levels of glutathione peroxidase and catalase in non-sensitized mice (p<0.05). These data suggest that the pulmonary anti-inflammatory effects produced by 3 weeks of high-intensity swimming in this model of OVA-induced asthma may be, at least partly, modulated by reduced oxidative stress and increased IL-10 production.

Stretch-induced nerve injury: a proposed technique for the study of nerve regeneration and evaluation of the influence of gabapentin on this model

The rat models currently employed for studies of nerve regeneration present distinct disadvantages. We propose a new technique of stretch-induced nerve injury, used here to evaluate the influence of gabapentin (GBP) on nerve regeneration. Male Wistar rats (300 g; n=36) underwent surgery and exposure of the median nerve in the right forelimbs, either with or without nerve injury. The technique was performed using distal and proximal clamps separated by a distance of 2 cm and a sliding distance of 3 mm. The nerve was compressed and stretched for 5 s until the bands of Fontana disappeared. The animals were evaluated in relation to functional, biochemical and histological parameters. Stretching of the median nerve led to complete loss of motor function up to 12 days after the lesion (P<0.001), compared to non-injured nerves, as assessed in the grasping test. Grasping force in the nerve-injured animals did not return to control values up to 30 days after surgery (P<0.05). Nerve injury also caused an increase in the time of sensory recovery, as well as in the electrical and mechanical stimulation tests. Treatment of the animals with GBP promoted an improvement in the morphometric analysis of median nerve cross-sections compared with the operated vehicle group, as observed in the area of myelinated fibers or connective tissue (P<0.001), in the density of myelinated fibers/mm² (P<0.05) and in the degeneration fragments (P<0.01). Stretch-induced nerve injury seems to be a simple and relevant model for evaluating nerve regeneration.

Glycogen synthase kinase 3-specific inhibitor AR-A014418 decreases neuropathic pain in mice: evidence for the mechanisms of action

The present study examined the antihyperalgesic effect of a specific inhibitor of Glycogen Synthase Kinase 3 (GSK3), AR-A014418, on the partial ligation of the sciatic nerve (PSNL), a neuropathic pain model in mice and investigated some mechanisms of action. AR-A014418 (0.01-1 mg/kg) administered by intraperitoneal route (i.p.) inhibited mechanical hyperalgesia. This action started 30 min after i.p. administration and remained significant up to 2 h. When administered daily for 5 days, AR-A014418 (0.3 mg/kg, i.p.) significantly reduced the mechanical hyperalgesia caused by PSNL. Intraperitoneal (i.p.) treatment with AR-A014418 (0.3 mg/kg) also significantly inhibited cold hyperalgesia induced by PSNL. Pre-administration of PCPA (100 mg/kg, i.p., inhibitor of serotonin synthesis) and AMPT (100 mg/kg, i.p., inhibitor of tyrosine hydroxylase), but not l-arginine (600 mg/kg, i.p., a nitric oxide precursor), significantly reduced the mechanical hyperalgesia elicited by AR-A014418. Furthermore, the administration of AR-A014418 significantly prevented the increase of TNF-α (inhibition of 76±8%) and IL-1β (inhibition of 62±10%), but did not alter lumbar spinal cord IL1-ra and IL-10 levels. Finally, intraperitoneal administration of AR-A014418 did not affect locomotor activity in the open-field test. Taken together, these results provide experimental evidence indicating that AR-A014418 produces marked antihyperalgesic effects in neuropathic pain in mice, possibly due to mechanisms that reduce proinflammatory cytokines, as well as increases in serotonergic and catecholaminergic pathways. The present study suggests that GSK3 may be a novel pharmacological target for the treatment of neuropathic pain and AR-A014418 might be a potential molecule of interest for chronic pain relief.

(-)-Linalool, a naturally occurring monoterpene compound, impairs memory acquisition in the object recognition task, inhibitory avoidance test and habituation to a novel environment in rats

It is known that (-)-linalool is a competitive antagonist of NMDA receptors, which play a key role in the learning and memory processes; however, only a few studies have reported a possible interference of (-)-linalool in memory. The purpose of this study was to investigate the (-)-linalool effects on acquisition of short- and long-term memories through the objects recognition task, inhibitory avoidance test and habituation to a novel environment. Furthermore, the open field test was used to investigate the interference of (-)-linalool in motivation, locomotion and exploration by animals. Wistar male adult rats received an intraperitoneal injection (i.p.) of saline (NaCl 0.9%), tween 5% or (-)-linalool (50 or 100 mg/kg) before training in the tasks; MK-801 (0.1 mg/kg), a glutamate antagonist, was used as positive control. Short-term (STM) and long-term (LTM) memories were tested 1.5 and 24 h after training, respectively, in the inhibitory avoidance and recognition objects. The results suggested that (-)-linalool (as 50- and 100-mg/kg doses) impaired LTM acquisition, but not STM acquisition, in the object recognition task. In the inhibitory avoidance test, animals receiving linalool (both doses) showed impairment in acquisition of both memories measured. In the open field test, the animals that received (-)-linalool showed no significant difference in the crossings and latency to start the locomotion in any of the doses tested, although (-)-linalool 100 mg/kg reduced rearing behavior. When re-exposed to open field 24 h after training, the rats that received (-)-linalool 100mg/kg showed no habituation. Taken together, these data suggested that (-)-linalool was able to impair the acquisition of memory in rats, which can be associated to (-)-linalool antagonist capacity as regards NMDA glutamatergic receptors, since other glutamate antagonists also seem to affect memory.

296 INFLUENCE OF SHORT-TERM HEAT STRESS ON THE BLASTOCYST RATE OF BOVINE EMBRYOS (INDICUS VS. TAURUS) FROM OOCYTES OBTAINED BY OVUM PICKUP

There is evidence that the deleterious effects of heat stress (HS) on fertility are less pronounced in Bos indicus than in B. taurus breeds, due primarily to differences in their thermoregulatory capacity. In the present work, the resistance to heat stress of Nelore embryos (B. indicus) was compared to either a breed not adapted (Angus; B. taurus) or adapted to high temperatures (Bonsmara; 5/8 B. indicus × 3/8 B. taurus). In Experiments (Exp.) 1 (Nelore vs. Angus) and 2 (Nelore vs. Bonsmara), oocytes obtained by ovum pickup OPU (during autumn) were matured (TCM-199), fertilized, and cultured (SOFaaci) in vitro. Ninety-six hours post-insemination (hpi), embryos with more than 16 cells were randomly allocated in two main groups: Group Control (embryos were maintained at 39°C all of the time) and Group HS (embryos were maintained at 41°C during 12 h and afterwards returned to 39°C). Blastocyst rates were determined on the 7th day of culture. In Exp. 1, 294 oocytes from Nelore and 144 from Angus cows had a cleavage rate of 67.9 and 59.4%, respectively. Ninety-six-hpi embryos (>16 cells) were distributed in four groups: Nelore Control (n = 97), Nelore HS (n = 95), Angus Control (n = 34) and Angus HS (n = 25). The blastocyst rates were 39/97 (40.2%), 23/95 (24.2%), 19/34 (55.9%), and e 8/25 (32.0%), respectively. The difference in rate of blatocyst formation caused by heat stress on Nelore (16.0%) and Angus (23.9%) was not significantly different (P < 0.05), and suggests, from oocytes obtained by OPU, that Nelore embryos may be more tolerant to HS than Angus embryos. However, it is necessary to increase the number of blastocysts per group in order to better characterize the effects of heat stress on these embryos. In Exp. 2, 294 oocytes from Nelore and 101 from Bonsmara cows had a cleavage rate of 41.2 and 51.2%, respectively. Ninety-six-hpi embryos (>16 cells) were distributed in four groups: Nelore Control (n = 44), Nelore HS (n = 49), Bonsmara Control (n = 22), and Bonsmara HS (n = 22). The blastocyst rates were 35/44 (79.5%), 30/49 (61.2%), 10/22 (45.5%), and 6/22 (27.3%), respectively. In spite of the fact that Bonsmara embryos had a lower blastocyst rate as compared to Nelore, the decline on blastocyst rate caused by HS was very similar in Nelore (18.3%) and Bonsmara embryos (18.2%). Additional OPU are underway to test the hypothesis that thermotolerance of Nelore embryos is similar to that in embryos from a breed adapted to high temperatures (Bonsmara), and superior to embryos from a non adapted breed (Angus). E. S. S., R. A. S., and M. F. G. N. were supported by a fellowship from FAPESP, and A. C. Z. B. by a fellowship from CAPES of Brazil.